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Infant handling (holding or carrying) by adult males is rare in mammals; however, high levels have been reported in some primates. Though infant handling is a costly behaviour, there are many benefits that male handlers can accrue. Infant handling by males is most conspicuous in platyrrhines and tends to be uncommon in catarrhines. In the latter species, research on male-infant interactions has focused on low-cost behaviours, such as proximity and grooming. However, to better understand the evolution of infant handling by males, more data on its occurrence across the Primate order are essential, even in species where it is relatively uncommon. We compare the occurrence of infant handling by males in three closely related species of catarrhine: Colobus vellerosus, C. guereza, and C. angolensis ruwenzorii. We collected focal animal samples on infants to quantify infant handling rates and durations, and found that adult male C. a. ruwenzorii handled infants much more frequently and for much longer than males in the other two species. We discuss how C. a. ruwenzorii's unique social organization may explain high levels of infant handling by adult males in this species. More long-term and detailed comparisons of infant handling across species and populations will shed light on how sociality has shaped the evolution of this behaviour in the Primate order.

Electric shock and electrocution affect at least 31 primate species, but studies of how electrical infrastructure affects primate populations are rare. We investigated 320 cases of electric shock and electrocution in four sympatric monkey species in Diani, Kenya, 1998–2019: Peters’s Angola colobus (Colobus angolensis palliatus), Zanzibar Sykes’s monkey (Cercopithecus mitis albogularis), Hilgert’s vervet (Chlorocebus pygerythrus hilgerti), and the Southern yellow baboon (Papio cynocephalus cynocephalus). These represent 16% of the total welfare cases reported to a local conservation organization. Deaths occurred in 73% of cases. The number of cases did not increase through the study period, presumably because mitigations implemented by the power distribution company and a local conservation organization offset the risks associated with the electrical infrastructure expansion. Colobus accounted for 80% (N = 256) of cases, representing ca. 4.6% of the population annually, which is likely unsustainable. Adult male colobus were shocked or electrocuted more than expected, while all other age–sex classes were involved in proportion to the population structure. The number of cases was low for Sykes’s monkey (13%, N = 42), vervets (5%, N = 16), and baboons (2%, N = 6). Our findings show that electrical infrastructure affects species differentially; larger arboreal species with individuals ≥8 kg are at higher risk of injury and death than smaller arboreal species and terrestrial species. Other organizations can estimate risks in their areas based on the factors we reviewed. Further understanding of how body mass impacts risk will have implications for designing electrical infrastructure as part of conservation planning.

Competition for food is often a cost associated with living in a group, and can occur in an indirect (scramble) or direct (contest) form. We investigated feeding competition in a supergroup of Rwenzori black-and-white colobus monkeys (Colobus angolensis ruwenzorii) in Rwanda, with the aim of establishing whether freedom from scramble competition allows these monkeys to form supergroups. We used the patch depletion method, measuring intake rate coupled with movement rate, to assess if food patches become depleted over the occupancy period. Resource depletion was evident when the colobus fed on young leaves, but not when feeding on mature leaves. Scramble competition was inferred from a negative correlation between group size and change in intake rate over patch occupancy. Between-group contest competition was inferred from displacement from patches. Although feeding competition exists for select resources, limited competition for mature leaves may enable Rwenzori colobus to live in a supergroup of hundreds of individuals in this montane forest.

Vocal behaviour offers a window into understanding the social life and evolution of animals. Colobine monkeys show great interspecific and interpopulation variation in their social organization and behaviour. Recent research has shown that Rwenzori Angolan colobus (Colobus angolensis ruwenzorii) differ substantially from other black-and-white colobus in forming a multi-level society. No previous research has been conducted on the communication of C. a. ruwenzorii, but the social complexity hypothesis for communication suggests that more complex societies should evolve more complex communication repertoires. Our objective was to catalogue the vocal repertoire of C. a. ruwenzorii at Nabugabo, Uganda, and to compare it with the data available on congeners regarding intergroup tolerance, vocal repertoire size, and acoustic and behavioural features of vocal communication. Vocalizations were subject to spectrographic and behavioural analysis, and a descriptive analysis of each vocalization type was made. The influence of a few environmental and social factors on calling rates was also examined. We describe five vocalizations (i.e., the snort, roar, squeak, scream and pok) and one non-vocal signal (i.e., the tongue click) in this subspecies and their contexts. Distinct alarm calls are made for dogs, and these are given more often near the edge of the forest where humans frequent. We did not find that C. a. ruwenzorii showed a greater vocal repertoire than C. guereza or C. polykomos, which do not live in multi-level societies. Further, preliminary data do not indicate greater calling rates in larger core units of C. a. ruwenzorii compared to smaller units. These findings support the view that these primates’ vocalizations tend to be relatively conserved despite large differences in social organization.

When preferred foods are scarce, one strategy employed by primates is to switch to an alternative food item of lower quality or preferability, i.e., a fallback food. In the montane rainforest of Nyungwe National Park in southwestern Rwanda, Rwenzori black-and-white colobus (Colobus angolensis ruwenzorii) (hereafter Rwenzori colobus) form a supergroup comprising hundreds of individuals. Over 13 mo we investigated how this supergroup uses resources in periods of resource abundance vs. periods of resource scarcity. Based on 5603 feeding records we first identified preferred foods and then identified fallback foods as those food categories or species whose consumption increases when preferred foods, or preferred food categories, are less available. When the availability of 19 preferred food items was low, fruticose lichens (Usnea sp.) contributed >50% of the monthly diet for the Rwenzori colobus. Moreover, consumption of lichens was significantly negatively related to the availability of preferred foods. Fruticose lichens can therefore be considered a fallback food for Rwenzori colobus that sustains the supergroup during periods of reduced food availability. This result, in combination with previous findings that mature foliage in Nyungwe is of high quality and does not elicit feeding competition, points to the importance of resources in facilitating supergroup formation. However, several other montane forests in Eastern Africa also harbor fruticose lichens and yet support only small groups of Angolan colobus, suggesting that additional factors such as sufficient forest size and limited fragmentation and hunting pressure by humans are required for supergroups to form.

The impacts of road infrastructure on wildlife are of mounting concern. Amidst a growing body of literature on vehicle–wildlife collisions, few studies focus on primates. We examined a long-term dataset (2000–2018) of community-reported welfare cases for four species of monkeys: colobus (Colobus angolensis palliatus), Sykes’s monkey (Cercopithecus mitis albogularis), vervet (Chlorocebus pygerythrus hilgerti), and baboon (Papio cynocephalus cynocephalus). We analyzed collision rates using annual census data along a 10-km road section through the suburban town of Diani, Kenya. Vehicle–monkey collisions represented 705 of 1896 cases (37%), which was the most common anthropogenic cause of injury and death. The mean number of monthly vehicle–monkey collisions was 3 (range 0–10), and 83% of collisions led to death of the monkey. We found 1) higher degrees of terrestrialism were associated with lower number of collision cases; 2) no differences in the collision rates between juveniles, subadults, and adults across species, but collisions involving infants occurred at lower rates; 3) similar collision rates for female and male colobus and baboons, whereas Sykes’s monkey females and vervet males were more frequently involved in collisions than the other sex; 4) no correlation between the number of hotel bed-nights (a measure of tourist numbers) and vehicle collisions; and 5) drier days correlated with increased rates of vehicle–monkey collisions across all species. This study highlights the risks of roads for monkeys, and that collision rates vary with species, age class, and, in some species, sex and that rainfall is one factor that affects these rates.

Large-scale anthropogenic changes to the environment are making it vital to investigate habitat use so that we can better understand species’ basic ecological needs in order to create successful conservation plans. Some species are very flexible in their habitat requirements. One such species may be Colobus angolensis ruwenzorii, monkeys that occupy montane and tropical lowland forest. In the mountains of southwestern Rwanda, this species spends a great deal of time on the ground and feeds mainly on mature leaves and lichens, but the habitat use of lower altitude populations is unknown. We examined the fine-scale habitat use of C. a. ruwenzorii at Nabugabo, Uganda (1136 m altitude), where they feed primarily on young leaves and fruits. We used data collected over 9 mo (94 days between July 2017 and April 2018) on 117–131 colobus in 12 core units in a multilevel society. We found that colobus individuals were rarely on the ground, and resting and social behavior occurred at higher heights and in larger trees than feeding and moving. Individual height in the canopy followed a daily pattern (higher at the start and end, with a decrease in the middle of the day) and colobus were at lower heights when group size was greater because of core unit fusion. Finally, we found that tree species were generally used relative to their availability in the forest and their value as food species. Given greater predation risk in smaller groups and lower in the canopy at this site, our results suggest that perceived risk has an important effect on microhabitat use in C. a. ruwenzorii at lower altitude. Our results demonstrate the ecological flexibility of this primate species, which bodes well for their continued conservation.

Most primates live in unprotected land where abundances and threats may differ from those in protected areas. We therefore need to establish population densities in both unprotected and protected areas to effectively inform conservation planning. The Greater Mahale Ecosystem in western Tanzania is a region of mixed protected status with seven cercopithecine and colobine species: blue (Cercopithecus mitis doggetti), red-tailed (C. ascanius schmidi), and vervet (Chlorocebus pygerythrus) monkeys; ashy red colobus (Piliocolobus tephrosceles); black-and-white colobus (Colobus angolensis); and olive (Papio anubis) and yellow (P. cynocephalus) baboons. These species may be threatened by increasing human activity; however, except for ashy red colobus, no data on local abundances are available. We walked over 350 km of line transects in legally protected (Village Forest Reserves) and unprotected general land between August 2011 and October 2012 to estimate densities of primates and human activity. Primate densities were consistently low across the Greater Mahale Ecosystem. Blue and red-tailed monkey and ashy red colobus densities were especially low compared to populations in predominantly forested landscapes. Primate and human activity densities did not differ significantly inside and outside of reserves. Low primate densities could be natural responses to the lower proportions and quality of riparian forest habitat in the region. High levels of human activity and the absence of significantly higher primate densities in reserves suggest unprotected land could provide important refuges for primates in the Greater Mahale Ecosystem. This result further reinforces a broad need to include unprotected areas in primate conservation strategies.

Introduction: Colobine monkeys are specialized folivores that use foregut fermentation to digest leaves. The slow process of fermentation forces them to spend a lot of time resting and to minimize their energy expenditure to subsist on a lower-quality diet. Methods: We recorded the diet and activity budget of Colobus angolensis ruwenzorii, which form a three-tiered multi-level society, at Lake Nabugabo, Uganda, over 12 months using scan sampling on adults and subadults, to determine whether they utilize the energy minimization strategy typical of colobines. Results: We found that the annual diet was primarily comprised of high-quality food resources (young leaves 65% and fruit 31%), and fruits were the only plant part the monkeys selected when available. Both the fruits and young leaves of some species were preferred food items in some months, and mature leaf consumption correlated negatively with preferred food availability. Mature leaves appear to be a fallback food for this population but are rarely relied upon (3%). The C. a. ruwenzorii at Nabugabo spent less time resting (40%) and more time moving (25%) than is typical for other species of black-and-white colobus. Discussion/Conclusion: The high-quality diet of this population appears to allow them to utilize an energy maximization strategy. Their reliance on food items that tend to be clumped in space and time likely explains the frequent fission-fusion behaviour that we observe between core units. Our findings demonstrate that the foraging strategies of colobines may be more flexible than was previously thought and illustrate how food availability and distribution can impact primate social organization.

Multi‐level societies are complex, nested social systems where basic social groups (i.e., core units) associate in a hierarchical manner, allowing animals to adjust their group sizes in response to variables such as food availability, predation, or conspecific threat. These pressures fluctuate over time and examining the extent to which this variation affects the clustering of core units into different tiers may be instrumental in understanding the evolution of multi‐level societies.The goal of our study was to determine the degree of temporal variability in interunit associations in a multi‐level society of Rwenzori Angolan colobus monkey (Colobus angolensis ruwenzorii), and to determine the social and ecological factors that underlie association patterns. The C. a. ruwenzorii multi‐level society consists of at least three tiers, with core units clustering into clans that share a home range in a band tier.We performed social network analyses on 21 months of association data from 13 core units (totaling 139 identifiable individuals) at Lake Nabugabo, Uganda. We described the patterns of variation in core‐unit associations over time and investigated how changes in rainfall, food availability, and interunit dispersals were correlated with these associations over the short‐term (month to month) and long‐term (year to year).Although clans were relatively stable, larger‐scale changes in association patterns included the formation of an all‐male unit and the transfer of one core unit between clans (within the band tier). Seasonally, core units associated significantly more when fruit, their preferred food source, was abundant (i.e., social networks were denser and more clustered) and there was no direct effect of rainfall seasonality or young leaf availability. Male dispersals also occurred more during periods of high fruit availability, suggesting that greater band cohesion allowed males to prospect and transfer between core units. Once males transferred, their previous and new units associated significantly more with one another than with other core units for 1–2 months postdispersal. The dispersal of five males from one core unit to another in a different clan co‐occurred with this core unit switching its clan affiliation.By examining temporal shifts in social network structure among core units, this study shows the interconnected roles that food availability and dispersal have in shaping the C. a. ruwenzorii multi‐level social system. Our findings highlight how ecological conditions can drive association patterns, impact interunit relationships, and influence social organization., Core units in a multi‐level society of Rwenzori Angolan colobus monkeys show temporal variation in association that corresponds to food availability. Units are more clustered when fruit is abundant and interunit dispersal by males also peaks at this time, suggesting that the seasonal pattern of band cohesion allowed males to prospect for dispersal opportunities. Our findings highlight how ecological conditions can influence association patterns, interunit relationships, and ultimately social organization.

Our understanding of the evolutionary history of primates is undergoing continual revision due to ongoing genome sequencing efforts. Bolstered by growing fossil evidence, these data have led to increased acceptance of once controversial hypotheses regarding phylogenetic relationships, hybridization and introgression, and the biogeographical history of primate groups. Among these findings is a pattern of recent introgression between species within all major primate groups examined to date, though little is known about introgression deeper in time. To address this and other phylogenetic questions, here we present new reference genome assemblies for three Old World Monkey species: Colobus angolensis ssp. palliatus (the black and white colobus), Macaca nemestrina (southern pig-tailed macaque), and Mandrillus leucophaeus (the drill). We combine these data with 23 additional primate genomes to estimate both the species tree and individual gene trees using thousands of loci. While our species tree is largely consistent with previous phylogenetic hypotheses, the gene trees reveal high levels of genealogical discordance associated with multiple primate radiations. We use strongly asymmetric patterns of gene tree discordance around specific branches to identify multiple instances of introgression between ancestral primate lineages. In addition, we exploit recent fossil evidence to perform fossil-calibrated molecular dating analyses across the tree. Taken together, our genome-wide data help to resolve multiple contentious sets of relationships among primates, while also providing insight into the biological processes and technical artifacts that led to the disagreements in the first place.

Primates display broad diversity in their social organization. The social groups of a few primate species are organized in a multilevel fashion, with large groups composed of multiple, core one-male units (OMUs). A characteristic of multilevel societies is that the higher levels can include hundreds of individuals. The Rwenzori black-and-white colobus (Colobus angolensis ruwenzorii) in the montane forests of Rwanda form supergroups and have been suspected to exhibit multilevel social organization. Here we present the first data on the "anatomy" of a supergroup numbering 500+ individuals. We identified subgroups within the supergroup based on progression data, extracting the social network structure from the time-stamped spatiotemporal distribution of passing individuals identified to age-sex class, and selecting an optimal time window for each network using the two-step approach developed by Uddin, Choudhury, Farhad, and Rahman (2017). We detail the existence of core units-multi-male units (MMUs) with a mean of 1.7 adult males and 3.1 adult females, as well as OMUs, all-female units and bachelor units composed of adult and sub-adult males. More than two-thirds of units are MMUs. These grouping patterns conform to a multilevel society with predominantly multi-male core units, a social system that has recently also been described for a population of the same taxon in Uganda. Individual identification will be required to corroborate these interpretations.

Yersinia enterocolitica (YE) bioserotype 1B/O:8 (YE 1B/O:8) was identified in routine culture of a variety of zoo species housed at Omaha's Henry Doorly Zoo and Aquarium (OHDZA) from April to July 2011. Animal cases representing 12 species had YE detected from 34 cases during routine fecal monitoring and/or during postmortem examination: Coquerel's sifakas (Propithecus coquereli, two cases), black & white (BW) ruffed lemurs (Varecia variegata variegata, six cases), red ruffed lemurs (Varecia rubra, seven cases), white handed gibbon (Hylobates lar albimana, one case), black lemurs (Eulemur macaco, three cases), mongoose lemurs (Eulemur mongoz, two cases), African hunting dogs (Lycaon pictus, five cases), agile gibbons (Hylobates agilis, three cases), siamangs (Hylobates syndactylus, two cases), colobus monkey (Colobus angolensis palliates, one case), argus pheasant (Argusianus argus, one case), and orangutan (Pongo pygmaeus, one case). Most species were not symptomatic; however, three symptomatic cases in Coquerel's sifakas (two) and a white handed gibbon (one) showed clinical signs of diarrhea and lethargy that resulted in death for the Coquerel's sifakas. One unexpected death also occurred in a BW ruffed lemur. To the authors' knowledge, this is the first report of YE 1B/O:8 in such a large variety of zoo species. The source of the YE could not be identified, prompting the initiation of a diseases surveillance program to prevent further cases for the species that are sensitive to YE. To date, no additional cases have been identified, thus suggesting a single introduction of the YE 1B/O:8 strain into the zoo environment.

Anogenital distance (AGD) is positively correlated to fetal androgen exposure and developmental masculinization in mammals. Independent of overall body size, AGD shows a strong positive correlation with male fertility and in rodents, AGD is a good indicator of male competitive ability and is associated with female choice. We hypothesized that AGD will also predict male competitive ability in non-human primates. To test this, we measured AGD noninvasively with a parallel laser in a wild population of Angolan colobus monkeys (Colobus angolensis ruwenzorii) in Uganda and correlated to it to their social structure. C. angolensis ruwenzorii form a multilevel society with both one-male/multifemale units (OMUs) and multimale/multifemale units (MMUs). We compared AGD in males from five OMUs and six MMUs and related it to their fecal androgen metabolite concentrations, dominance rank and body size, and to the number of females in their unit. Males in OMUs had greater access to females, so were predicted to have longer AGDs, but this was not found. AGD also did not correlate overall with mean fecal androgen metabolites in MMUs. However, AGD was correlated with dominance rank in MMUs, demonstrating that higher-ranking males in these multimale units had longer AGDs. Body size did not show the same relationship with dominance rank, suggesting that male rank was not just a reflection of absolute male size. Our findings indicate that AGD predicts male competitive ability in this species and that it may be a useful correlate throughout the non-human primates. These results also support the idea that prenatal androgen exposure increases the likelihood of the expression of behaviors that maintain high dominance rank.

Electrocution from power infrastructure threatens many primate species, yet knowledge of effective evidence-based mitigation strategies is limited. Mitigation planning requires an understanding of the spatial distribution of electrocutions to prioritize high-risk areas. In Diani, a coastal Kenyan town, electrocution is an important cause of death for five primate species. In this study we aim to describe the spatial patterns of electrocutions and electric shock incidents (collectively referred to as electrocutions hereafter) and identify electrocution hotspots to guide an effective primate conservation approach in Diani. Colobus Conservation, a not-for-profit organization, has recorded electrocutions and annual primate census data since 1998. We georeferenced 329 electrocution data points and analyzed them using QGIS. We identified and compared hotspots across species, seasons, and time using kernel density estimation and Getis-Ord-Gi*. We employed spatial regression models to test whether primate population density and power line density predicted the location of electrocution hotspots. Electrocutions occurred in hotspots that showed little variation in location between species and seasons. The limited variation in hotspot location over time likely occurred as a result of new building development in Diani and variability in primate detection rates by community members. Primate density and power line density were significant predictors of electrocution density for Angolan black-and-white colobus (Colobus angolensis palliatus) and Sykes monkeys (Cercopithecus mitis albogularis), but the relationship was weak, suggesting the presence of additional risk factors. This study provides a framework for systematic spatial prioritization of power lines that can be used to reduce primate electrocutions in Diani, and can be adopted in other areas of the world where primates are at risk from electrocution. Electronic supplementary material The online version of this article (10.1007/s10764-018-0046-6) contains supplementary material, which is available to authorized users.

Close proximity and social grooming are important bonding mechanisms in primates. These behaviors show the social structure of a species and many studies have found positive correlations between the degree of kinship and grooming and proximity. We used 1 year of data collected via instantaneous scan sampling on a large "supertroop" of Colobus angolensis ruwenzorii at Lake Nabugabo, Uganda, to examine partner preferences for grooming and nearest neighbors in each age-sex class. Little is known about this species, so we based our hypotheses on congeners. Of the five species of black-and-white colobus, data on sex-biased dispersal patterns are available for three (C. guereza, C. vellerosus, and C. polykomos), all of which show male-biased dispersal with occasional female dispersal. We thus predicted that female C. a. ruwenzorii would be more strongly bonded than males, showing greater proximity and grooming. We did not expect bonding between the sexes since congeners do not show this pattern. We found that among adult dyads, males and females were more likely to be found in loose proximity, and to groom, than would be expected given group composition. Conversely, both males and females had relatively weak same-sex relationships. Between the sexes, adult males had higher proximity and grooming indices with adult females without infants than with females with infants. These observations indicate that this subspecies is cross-bonded and that both sexes may disperse. Furthermore, our findings suggest that the social organization and social structure of C. a. ruwenzorii differ greatly from other black-and-white colobus species.

Behavioral and dietary flexibility permits primates to survive in variable environments. It is clear that some species cope with habitat disturbance and fragmentation better than others. I examined the dietary flexibility of Colobus angolensis palliatus by studying three groups inhabiting structurally distinct ranges in Kenya’s Diani Forest. I predicted that the two groups inhabiting more disturbed areas would have reduced food availability and would respond by increasing dietary diversity and consuming greater proportions of lianas and exotic plant species compared to the group inhabiting the more intact area. Forest composition and overall plant part availability differed among home ranges; however, group diets did not differ in their proportions of different plant parts, nor did groups select plant parts in proportion to their availability. Diets differed dramatically with regard to species-specific plant parts, i.e., mean monthly dietary overlap among groups = 10.4%. Contrary to my predictions, all three groups exhibited considerable dietary diversity, i.e., 63–76 plant species, and relied heavily on lianas, i.e., 20.8–38.4% of the diet, and exotic plant species, i.e., 30.1–40.3% of the diet. The presence of exotic plant species in all three ranges suggests that even the most intact areas of the Diani Forest are perturbed and should be classified along a spectrum of habitat disturbance rather than intact vs. degraded. Nonetheless, this study emphasizes that diets can vary considerably among groups living in the same forest, and this degree of dietary flexibility likely enables C. a. palliatus to survive within increasingly disturbed habitats.

Accurate estimations of the abundance of threatened animal populations are required for assessment of species' status and vulnerability and conservation planning. However, density estimation is usually difficult and resource demanding, so researchers often collect data at local scales. However, anthropogenic pressures most often have landscape-level effects, for example, through habitat loss and fragmentation. We applied hierarchical distance sampling (HDS) to transect count data to determine the effect of habitat and anthropogenic factors on the density of 3 arboreal primate species inhabiting 5 distinct tropical forests across a landscape of 19,000 kmEfectos de la Perturbación Antropogénica sobre la Densidad de Primates a Escala de Paisaje Resumen Se requieren estimaciones correctas del tamaño de las poblaciones de animales amenazados para evaluar el estado y la vulnerabilidad de las especies y así planear su conservación. Sin embargo, la estimación de la densidad es usualmente complicada y demanda recursos, así que los investigadores con frecuencia recolectan la información a escala local, a pesar de que la presión antropogénica suele tener efectos a nivel del paisaje; por ejemplo, la pérdida del hábitat y la fragmentación. Aplicamos un muestro jerárquico a distancia (HDS, en inglés) para contar datos por transecto y determinar el efecto de los factores del hábitat y los factores antropogénicos sobre la densidad de tres especies de primates arbóreos en un paisaje de 19,000 km物种濒危等级、易危性的评估及保护规划需要对濒危动物种群数量进行准确估计。但是密度估计通常较为困难, 且对资源的需求较高, 因此研究者一般只能收集局部尺度的数据。然而, 人为压力的影响常常是景观尺度的, 例如导致生境丧失和破碎化。我们在坦桑尼亚乌德宗瓦山脉 (Udzungwa Mountains) 19,000 平方千米的景观尺度中, 采用分层距离取样法收集样带计数数据, 确定了生境和人为因素对三种栖息在五个不同的热带森林树栖灵长类物种种群密度的影响。我们发展了一种新的多区域分层距离取样法, 可以在不丢失位置特异信息的情况下对跨越多个森林的物种种群密度和可探测性统一建模。对所有这三个物种来说, 人为干扰对集合种群密度的影响整体上都是负面的: 安哥拉疣猴 (Colobus angolensis palliatus) 为 −0.63 (95 % 贝叶斯置信区间为 −1.03 到 −0.27); 乌德宗瓦红疣猴 (Procolobus gordonorum) 为 −0.54 (95 % 贝叶斯置信区间为 −0.89 到 −0.22); 青猴 (Cercopithecus mitis monoides) 为 −0.33 (95 % 贝叶斯置信区间为 −0.63 到 −0.07) 。它们对生境因素的响应有共同之处, 特别是海拔的负面影响和攀缘植物覆盖度的积极作用。这些结果对保护科学和实践十分重要, 因为种群间对人为干扰共同的负面响应为发展景观尺度上的保护计划提供了基础, 这样的保护实践更为全面且成本效益高; 物种间的响应一致性则表明保护措施可能可以推广到多物种水平, 考虑到灵长类动物对热带雨林的重要功能, 这一点意义重大; 而灵长类在海拔低、与人类居住地较近的地区密度更高, 这指明了具体的管理建议, 例如确立缓冲区和优先保护区域。【翻译: 胡怡思; 审校: 聂永刚】.

Our understanding of the evolutionary history of primates is undergoing continual revision due to ongoing genome sequencing efforts. Bolstered by growing fossil evidence, these data have led to increased acceptance of once controversial hypotheses regarding phylogenetic relationships, hybridization and introgression, and the biogeographical history of primate groups. Among these findings is a pattern of recent introgression between species within all major primate groups examined to date, though little is known about introgression deeper in time. To address this and other phylogenetic questions, here, we present new reference genome assemblies for 3 Old World monkey (OWM) species: Colobus angolensis ssp. palliatus (the black and white colobus), Macaca nemestrina (southern pig-tailed macaque), and Mandrillus leucophaeus (the drill). We combine these data with 23 additional primate genomes to estimate both the species tree and individual gene trees using thousands of loci. While our species tree is largely consistent with previous phylogenetic hypotheses, the gene trees reveal high levels of genealogical discordance associated with multiple primate radiations. We use strongly asymmetric patterns of gene tree discordance around specific branches to identify multiple instances of introgression between ancestral primate lineages. In addition, we exploit recent fossil evidence to perform fossil-calibrated molecular dating analyses across the tree. Taken together, our genome-wide data help to resolve multiple contentious sets of relationships among primates, while also providing insight into the biological processes and technical artifacts that led to the disagreements in the first place., Combining three newly sequenced primate genomes with other published genomes, this study adapts a little-known method for detecting ancient introgression to genome-scale data, revealing multiple previously unknown examples of hybridization between primate species.

1 Objectives Examining the relationships among foraging behavior, food mechanical properties, and masticatory morphology is a bourgeoning research topic among behavioral ecologists and functional morphologists. The purpose of this study was to assess the degree to which leaf toughness influences foraging efficiency with regard to ingestion rate, masticatory investment, and masticatory rate. 2 Methods Diet and feeding data were collected on adults from three groups of Colobus angolensis palliatus in the Diani Forest, Kenya, from July 2014 to December 2015. Ingestion rates were estimated by counting the number of items consumed during feeding bouts and multiplying this value by the mean mass of a particular food item. The number of mastications was also counted during 3–5 minute focal periods. Mechanical toughness of commonly eaten young leaves (n = 27 species) and mature leaves (n = 13 species) was recorded using a toughness tester equipped with a razor blade. 3 Results Ingestion rates (g/min) negatively correlated with leaf toughness (r2 = 0.73; p

Several mammalian species exhibit complex, nested social organizations, termed multi-level or modular societies. Multi-level societies comprise stable core units that fission and fuse with one another in a hierarchical manner, forming groups that vary in size over time. Among nonhuman primates, these social systems have been confirmed in several African papionin and Asian colobine species. We use data from August 2017 to July 2018 on individually-recognized Rwenzori Angolan colobus living near Lake Nabugabo, Uganda to document the first multi-level society in an African colobine. The study band comprised up to 135 individuals organized into 12 socially and spatially distinct core units that ranged in size from 4 to 23 individuals. These core units showed a strong affinity to one another, spending roughly 75% of their time together. Core units fissioned and fused non-randomly with one another throughout the day, leading to different combinations of core units being observed. Using association indices between core units, we employed hierarchical cluster analyses and permutation tests to show that some core units associated preferentially into clans. Thus, we confirm three tiers of social organization for Rwenzori Angolan colobus: core unit, clan, and band. The social organization of this subspecies is unlike any reported previously in a nonhuman primate, with about half the core units containing a single adult male and the others containing multiple reproductive adult males. The discovery of a unique primate multi-level society in a novel lineage could allow for a better understanding of the evolution of these complex social systems across the Animal Kingdom. Preliminary data show males transfer within the band and females transfer outside of the band, which is proposed for hominin multi-level societies. This subspecies could thus also provide insight into the selective pressures underlying multi-level societies in our own lineage.

Ecological niche models can be useful for clarifying relationships between environmental factors and a species' geographic distribution. In this study, we use presence-only data and environmental layers to create an ecological niche model to better understand the distribution of the East African Angolan black and white colobus monkey, Colobus angolensis palliatus, and to assess whether the model supports considering the population as two separate subspecies, Colobus angolensis sharpei and C. a. palliatus. We found the range of the predicted distribution for suitable habitat of C. a. palliatus as currently classified to be only 12.4% of that shown in the International Union for Conservation of Nature Red List range map and to be fragmented. As C. angolensis is considered a "Least Concern" species, this difference suggests that generalized maps may lead to understating the species' extinction risk. When presence points were divided into two previously proposed subspecies -C. a. palliatus (Kenya and Northern Tanzania) and C. a. sharpei (Southern Tanzania)-we found significant environmental differences between the distributions. The most important ecological variable for C. a. palliatus was predominantly precipitation of the driest month (69.1%) whereas for C. a. sharpei annual precipitation (44.8%) and land cover (normalized difference vegetation index, 16.4%) were the most important. When comparing suitable ranges for the separate distributions, we found only a 1.2% geographical overlap. These differences are consistent with previous subspecies delineations of C. a. palliatus and C. a. sharpei based upon morphology, pelage, and genetics. Our study suggests that extirpation of C. a. palliatus in suitable habitat areas and occurrence of this subspecies in anthropogenic environments, warrant further consideration for conservation actions.

The elusive, Vulnerable owl-faced monkey Cercopithecus hamlyni is a rare and little studied species and one of the least known of the African Cercopithecidae. This study describes the distribution and relative abundance of the only known population in East Africa, in Nyungwe National Park, Rwanda. This species is restricted to a small (32 km2) area of bamboo and bamboo–forest mix in the southern sector of the Park, close to the international border with Burundi. We present the first empirical data of its abundance in the bamboo forests of Nyungwe. A total length of 185 km of transect were surveyed to estimate relative abundance of diurnal primates. Encounter rates with the owl-faced monkey were 0.081 groups km-1 (n = 15). Mean group size was 3.6 individuals. Eight independent photographs of C. hamlyni were obtained from five camera traps during 182 camera-days. Four other species of primates occur in the bamboo forest: eastern chimpanzee Pan troglodytes schweinfurthii, Angola colobus Colobus angolensis, L’Hoest’s monkey Cercopithecus l’hoesti and blue monkey Cercopithecus mitis. The main threats to the bamboo forest are from the illegal harvesting of bamboo, trapping and tree-cutting. These threats originate from both Rwanda and Burundi. There is an urgent need for conservation action to halt the destruction and degradation of the bamboo forest and to ensure the long-term survival of the owl-faced monkey in Rwanda.

Understanding intraspecific behavioral and dietary variation is critical for assessing primate populations' abilities to persist in habitats characterized by increasing anthropogenic disturbances. While it is evident that some species exhibit considerable dietary flexibility (in terms of species-specific plant parts) in relation to habitat disturbance, it is unclear if primates are characterized by similar variation and flexibility regarding nutrient intake. This study examined the effects of group, season, and reproductive state on nutrient intake and balancing in adult female Colobus angolensis palliatus in the Diani Forest, Kenya. During July 2014 to December 2015, estimates of nutrient intake were recorded for eight females from three groups inhabiting structurally and ecologically distinct forest areas differing in tree species composition and density. There were differences in metabolizable energy (ME) and macronutrient intakes among groups, seasons, and reproductive states. Most notably, females inhabiting one of the more disturbed forest areas consumed less ME and macronutrients compared to females in the more intact forest area. Contrary to prediction, females in early lactation consumed significantly less ME and macronutrients compared to non-lactating and late lactation females. Despite differences in macronutrient intake, the relative contribution of macronutrients to ME were generally more conservative among groups, seasons, and reproductive states. Average daily intake ratios of non-protein energy to available protein ranged from approximately 3.5:1-4.3:1 among groups. These results indicate that female C. a. palliatus demonstrate a consistent nutrient balancing strategy despite significant intergroup differences in consumption of species-specific plant parts. Data from additional colobine species inhabiting different forest types are required to assess the extent to which nutrient balancing is constrained by phylogeny or is more flexible to local ecological conditions.

To investigate relationships between ecology and social organization, observations were made on several populations of Colobus guereza in East Africa in 1970-74. Study time was concentrated in the Kibale Forest and the Kabalega National Park, Uganda. Findings on social behaviour are reported in this paper. Assessments of group composition were made. The repertoire of communicatory acts was analysed. During five-day continuous observation periods at Kibale (12 consecutive months) and at Kabalega (two months) all social interactions between members of one habituated group, and between this group and others, were recorded. 6 Kibale groups were monitored over a four-year period to examine changes in group structure. The results are compared with those from other studies and the adaptive significance of guereza social behaviour is discussed, emphasizing differences in male and female strategies.

Ruminants are characterized by an efficient particle-sorting mechanism in the forestomach (FRST) followed by selective rechewing of large food particles. For the nonruminating foregut fermenter pygmy hippo it was demonstrated that large particles are excreted as fast as, or faster than, the small particles. The same has been suggested for other nonruminating foregut fermenters. We determined the mean retention time of fluids and different-sized particles in six red kangaroos (Macropus rufus), seven collared peccaries (Pecari tajacu) and three colobine monkeys (Colobus angolensis, C. polykomos, Trachypithecus johnii). We fed Co-EDTA as fluid and mordanted fiber as particle markers (Cr, Ce). Mean (+ or - SD) total tract retention time for fluids, small and large particles was 14 + or - 2, 29 + or - 10 and 30 + or - 9 hr in red kangaroos, 26 + or - 2, 34 + or - 5 and 32 + or - 3 hr in collared peccaries and 57 + or - 17, 55 + or - 19 and 54 + or - 19 hr in colobine monkeys, respectively. Large and small particles were excreted simultaneously in all species. There was no difference in the excretion of fluids and particles in the colobine monkeys, in contrast to the other foregut fermenters. In the nonprimate, nonruminant foregut fermenters, the difference in the excretion of fluids and small particles decreases with increasing food intake. On the contrary, ruminants keep this differential excretion constant at different intake levels. This may be a prerequisite for the sorting of particles in their FRST and enable them to achieve higher food intake rates. The functional significance of differential excretion of fluids and particles from the FRST requires further investigations.

We documented the occurrence and abundance patterns of Angola black-and-white colobus (Colobus angolensis palliatus) in 46 coastal forest fragments ranging from 1 ha to >1400 ha in the Kwale District, Kenya. In field surveys conducted in 2001, we also recorded forest spatial, structural, resource, and disturbance characteristics to determine the effects of habitat quality and fragmentation and the factors most critical to the continued survival of the little-known species. We tested 13 hypotheses to explain variation in patch occupancy and abundance patterns of Colobus angolensis palliatus in relation to habitat attributes. Minimal adequate models indicated that the occurrence of colobus in forest fragments is positively associated with fragment area and canopy cover, whereas the density of colobus in occupied fragments is attributable to forest area, the proportion of forest change over the previous 12 yr, and the basal area of 14 major food trees. Large-scale illegal extraction of major colobus food trees in the District for human resource use, in both protected and unprotected forests, together with ongoing forest clearance and modification, are the major threats to Colobus angolensis palliatus in Kenya.

The Angola black-and-white colobus (Colobus angolensis palliatus) is a flagship species for Kenya's coastal forests, a global biodiversity hotspot and a region for “priority” conservation investment. This study provides the first evaluation of colobus distribution, status, and current threats within its Kenyan range: the southern coastal District of Kwale. Line transect and sweep count surveys were carried out between July and November of 2001, covering 25,514 ha of coastal forest within 124 forest fragments. A total of 55 colobus populations were located, with total Kenyan C. a. palliatus population estimates ranging between 3,100 and 5,000 individuals (560–900 groups). The Shimba Hills National Reserve protects both the largest forest and largest colobus population in the District. A total of 3,000 ha of coastal forest (12%) still remain unprotected and provide critical habitat for over 17% of the national colobus population. The Diani and Shimoni forests in particular, are highlighted as key habitat for future colobus (and coastal forest) conservation initiatives. Local semistructured interviews and archival research into the historical distribution of the taxon in North Coast Kenya confirmed its occurrence (and subsequent range contraction) in the Kilifi District, with the last sightings occurring in the Arabuko Sokoke Forest in 1979. Differences in the settlement distribution, associated habitat loss and hunting preferences of the nine coastal tribes (Mijikenda) may explain why colobus have disappeared from the north coast, but persist in the south. Am. J. Primatol. 69:664–680, 2007. © 2007 Wiley-Liss, Inc.

With group sizes sometimes >300 individuals, the Angolan black-and-white colobus (Colobus angolensis ruwenzorii) population in Nyungwe Forest, Rwanda is an intriguing exception to the tendency for folivores to live in smaller groups than expected relative to body size. Researchers have hypothesized that the unusually high quality of foliage at Nyungwe allows colobus there to avoid intragroup feeding competition, releasing constraints on the formation of large groups (Fimbel et al., 2001). We collected data on the activity and ranging patterns of a >300-member Nyungwe colobus group and compared our results to those from smaller groups in other black-and-white colobus (Colobus spp.) populations. Colobus at Nyungwe spent far more time feeding and moving (62%) and far less time resting (32%) than black-and-white colobus at any other site. The annual home range of the Nyungwe colobus was also many times larger (95% minimum convex polygon: 20.7 km 2 ; 95% fixed kernel: 24.4 km 2 ) than those for other populations. We terminated our research after the group engaged in an unprecedented migration among black-and-white colobus by moving 13 km south of their former range. Our results suggest that intragroup scramble competition may be more intense than originally believed within the large colobus groups at Nyungwe and that long periods of resource renewal may be necessary after a large colobus group passes through an area, thereby potentially helping to explain their wide ranging patterns. We discuss the socioecological convergence between the Nyungwe colobus and Chinese snub-nosed monkeys (Rhinopithecus spp.) and suggest directions for future research on the unique black-and-white colobus population at Nyungwe.

Many threatened primates now exist in fragmented forest habitats. The survival of these populations may depend on their ability to utilise agricultural or other matrix habitats between forest fragments, but this is poorly known. Here, we systematically investigate an arboreal primate’s use of a heterogeneous matrix in a fragmented forest landscape: the Angola black-and-white colobus ( Colobus angolensis palliatus ) in southern Kenya. We used a novel technique, based on semi-structured interviews with local informants, to address the difficulty of sampling relatively rare but important events, such as dispersal between fragments. We found that colobus frequently travelled and foraged in indigenous matrix vegetation (such as mangrove, wooded shrubland and shrubland) up to 4 km from the nearest forest fragments. Agricultural habitats, such as perennial plantation (coconut, mango and cashew nut) were also used by colobus for travelling and foraging (in remnant indigenous trees). The probability of sighting colobus in the matrix increased with the proportion of both tall (>6 m) vegetation cover and food tree cover, but declined with distance from forest habitat. Our findings suggest that certain matrix habitats are important for C. a. palliatus , and that future primate conservation initiatives might benefit from adopting a ‘landscape-level’ approach to habitat management, particularly in fragmented forest systems.

Identifying the nutritional composition of food items has significant ramifications for primate feeding ecology, which, in turn, influences investigations of primate sociality, cognition, and conservation. The aim of our study was to analyze water soluble carbohydrate (WSC) concentrations in the leaves of trees common to the Diani Forest of Kenya. Many of these leaves are consumed by black and white colobus monkeys (Colobus angolensis palliatus). We assessed whether the infrared spectral data collected using a portable spectrometer can be used to accurately predict WSC concentrations. WSC content was first quantified using the phenol-sulfuric acid method for young and mature leaves of 24 species and ranged from 1.15% to 9.16% dry weight. Spectral data were recorded with a spectrometer equipped with an attenuated total reflectance accessory (Agilent Cary 630) and analyzed using partial least squares regression. The spectral region from 1600 cm(-1) to 1000 cm(-1) gave unique polysaccharide bands associated with carboxyl, acetyl, and glycosidic linkages of sugar residues. The multivariate analysis gave excellent performance parameters with correlation coefficient (r(2) ) of 0.95 and standard error of cross-validation of 0.6% WSC. We found that IR spectroscopy provides a rapid and accurate technique for analyzing WSC concentrations and offers primatologists many advantages over wet chemistry methods for analyzing nutritional composition. Am. J. Primatol. 78:701-706, 2016. © 2016 Wiley Periodicals, Inc.

Infant adoption has been reported in a variety of primate taxa both in captive and natural settings. Adoption by females may be adaptive by increasing inclusive fitness via shared genes between adoptive mother and adoptee or by providing valuable maternal practice which, in turn, may increase the female's future reproductive success. Others have argued that adoption may be non-adaptive and the result of a general attraction toward infants. Our study examines a unique case of adoption by an adult female Angola black and white colobus monkey (Colobus angolensis palliatus) who adopted an extra-group infant alongside her own biological infant. We compare infant behaviors and mother-infant interactions between biological infant and adoptee and then compare both biological infant and adoptee behavioral profiles to those of infants under normal circumstances. Data were collected from July 2014 to June 2015 on three habituated groups in the Diani Forest of Kenya. Scan sampling and pooled data were used to create daily and monthly behavioral profiles for the biological infant and adoptee, as well as a mean monthly profile of four infants under normal circumstances. Data include time spent (1) clinging to mother/adoptive mother, (2) clinging to another individual, (3) behaving independently, and (4) behaving in close proximity to mother/adoptive mother. Initially, the adoptee struggled to achieve behavioral profiles consistent with those of the biological infant and normal colobus infants of the same age as he spent significantly more time moving independently and significantly less time clinging to the adoptive mother. After the mysterious death of the biological infant in mid-January 2015, the adoptee assumed a behavioral profile similar to that of infants under normal conditions. This case does not support adaptive hypotheses for adoption (i.e., inclusive fitness or learning to mother). Instead, because the biological infant died, possibly due to the presence of the adoptee, we argue that this case of infant adoption was non-adaptive. Ultimately, this adoption appears to have been an outcome of the adoptee's persistent desire to be cared for and the female's strong propensity to engage in allomaternal behavior.

With persistent degradation of tropical forests creating fragmented landscapes, the study of patterns of primate responses to habitat changes is of increasing conservation relevance. We modeled primate abundance in the Udzungwa Mountains of Tanzania through a landscape approach, i.e., one that includes a representative range of discrete forest blocks. The area is internationally recognized for biological endemism and is a primate hotspot in Africa. We targeted three predominantly arboreal monkeys: Udzungwa red colobus (Procolobus gordonorum), Peters’ Angola colobus (Colobus angolensis palliatus), and the Tanzania Sykes’ monkey (Cercopithecus mitis monoides). In each of the four forests (12–522 km2 in size), we counted primate groups along a grid of line transects (267 km walked) and sampled canopy trees in vegetation plots along the same transects (N = 408) to derive structural and floristic forest parameters and proxies of human impact. We found that elevation and the percentage of climber coverage on trees consistently emerged as significant predictors of primate abundance for all three species in spite of their differences in feeding habits, with a negative effect of elevation and a positive effect of climber coverage. This pattern held despite large variations in elevation, forest habitat, and human disturbance across the four forests surveyed. We conclude that arboreal primates in the Udzungwas are dependent on lowland and medium-elevation forests (ca. 300–1200 m a.s.l.) and show considerable resilience to moderate forest disturbance. However, agricultural intensification causes rapid forest degradation, with detrimental effects on primates that need to be prevented through increased protection and community conservation.

Many individual researchers have used line transect counts to estimate forest primate abundance. They have devoted less attention to the interpretation of line transect data obtained by several observers, as is often the case in long-term monitoring programs. We present primate relative abundance data that 5 observers collected over 6 yr (not continuous) along 4 different transects each 4 km long in the Mwanihana Forest, Udzungwa Mountains National Park, Tanzania. Total distance walked during transect repetitions is ca. 700 km. The species we saw most frequently was the endemic Udzungwa red colobus Procolobus gordonorum (mean 0.59 groups/km walked), followed by the Angolan black-and-white colobus Colobus angolensis (0.43 groups/km) and Sykes’s monkey Cercopithecus mitis (0.35 groups/km). We sighted the endemic Sanje mangabey Cercocebus galeritus sanjei and the yellow baboon Papio cynocephalus infrequently, the latter being confined to the deciduous forest parts of the transects. We analyzed sighting frequency by gross habitat type, transect, season, and observer. Interobserver differences in the relative abundance of each species were moderate and the few cases of significant variations were due to discordance of only 1 observer from the others. Estimated distances of primate group sightings differ significantly among observers, thus preventing us from deriving estimates of absolute density. Frequency distributions of distance-class intervals are not significantly different among observers, which may indicate gross interobserver consistency in the width of the area sampled. We conclude that unless consistency in data collection is checked, as we did for 2 observers who collected data simultaneously, potential interobserver differences remain an underlying source of variance in the results that cannot be separated from other sources of variance.

The effects of human activity on population and social structure are a pantropical concern for primate conservation. We compare census data and social group counts from two forests in the Udzungwa Mountains, Tanzania. The main aim is to relate differences within and between the forests to current theory on the effect of human disturbance on primate abundance and group size. The survey reveals the presence of the restricted-range red colobus, Procolobus gordonorum, in New Dabaga/Ulangambi Forest Reserve (NDUFR). The primate community of NDUFR is impoverished compared to that in Ndundulu forest. Red colobus and black-and-white colobus (Colobus angolensis palliatus) abundance and group size are lowest in NDUFR. Fission-fusion of red colobus social groups may be occurring in previously logged areas of both forests. Our observations are consistent with current theory on the effect of habitat degradation and hunting on primates, but the relative effects of the 2 factors could not be differentiated. We pooled the results with previous data to show that abundance of red colobus in the Udzungwa Mountains is lowest at high elevations. Low red colobus group sizes appear to be related to human activity rather than elevation. Black-and-white colobus and Sykes monkeys ( Cercopithecus mitis) show no relationship with elevation. Future studies will require more detailed information on vegetation, diet and ranging patterns to interpret fully intraspecific variation in population demography and social structure in the Udzungwa Mountains.

Estimates of population density and abundance are essential for the assessment of nonhuman primate conservation status, especially in view of increasing threats. We undertook the most extensive systematic primate survey yet of the Udzungwa Mountains of Tanzania, an outstanding region for primate endemism and conservation in Africa. We used distance sampling to survey three arboreal monkey species, including the endangered and endemic Udzungwa red colobus (Procolobus gordonorum). Overall, we encountered 306 primate clusters over 287 km walked along 162 line transects. We found the lowest cluster densities for both red colobus and Angolan colobus (Colobus angolensis; 0.8 clusters/km2) in the least protected forest (Uzungwa Scarp Forest Reserve, US), while we found the highest densities (3.2 and 2.6 clusters/km2 for red colobus; 3.2 and 2.7 clusters/km2for Angolan colobus) in two large and protected forests in the national park. Unexpectedly, Magombera, a small forest surrounded by plantations, had the highest densities of red colobus (5.0 clusters/km2), most likely a saturation effect due to the rapid shrinking of the forest. In contrast, Sykes’ monkey (Cercopithecus mitis monoides/moloneyi) had more similar densities across forests (3.1–6.6 clusters/km2), including US, suggesting greater resilience to disturbance in this species. For the endemic red colobus monkey, we estimated an abundance of 45–50,000 individuals across all forests, representing ca. 80% of the global population. Though this is a relatively high abundance, the increasing threats in some of the Udzungwa forests are of continued concern for the long-term survival of red colobus and other primates in the area.

Angolan black-and-white colobus monkeys (Colobus angolensis, Sclater 1980) in the Nyungwe Forest Reserve, Rwanda, are anomalous compared with conspecifics and congeners elsewhere, because they form exceptionally large groups, in excess of 300 individuals, and because of their unusually high consumption of mature leaves (∼40% of annual diet). Site factors at the Nyungwe Forest in southern Rwanda are believed to contribute to the unusual socio-ecology of the C. angolensis residing there. Foremost, the forest provides an abundance of mature leaves that are higher in nutritional quality (protein : fibre) compared with mature leaves analysed at other African sites. The combination of a cool high elevation locale, and a relatively open canopy, may contribute to the production of high quality mature leaves at ground level and in the canopy at the Nyungwe Forest. We believe that the almost unrestricted availability of acceptable foods for Nyungwe's folivorous colobines minimizes the potential for exploitation competition for food, and is a key factor in allowing them to form exceptionally large groups. Resume Les colobes noir et blanc d'Angola (Colobus angolensis, Sclater 1980) vivant dans la Reserve Forestiere de Nyungwe, au Rwanda, presentent des anomalies si on les compare aux autres membres de l'espece et leurs congeneres d'ailleurs, parce qu'ils forment des groupes exceptionnellement grands, depassant 300 individus, et a cause de leur consommation inhabituellement elevee de feuilles matures (≅40% du regime annuel). On pense que les caracteristiques du site de la Foret de Nyungwe, au sud du Rwanda, contribuent a la socio-ecologie inhabituelle des C. angolensis qui y vivent. Avant tout, cette la foret procure une abondance de feuilles matures de qualite nutritionnelle superieure (proteines et fibres) a celle relevee dans les feuilles matures analysees dans d'autres sites africains. La combinaison d'une altitude locale elevee avec temperature frai^che et d'une canopee relativement ouverte peut contribuer a la production de feuilles matures de haute qualite tant au niveau du sol que de la canopee de la Foret de Nyungwe. Nous pensons que la disponibilite quasi illimitee de nourriture acceptable pour les colobes mangeurs de feuilles de Nyungwe minimise la competition pour l'exploitation de la nourriture et qu'elle est un facteur cle dans la formation de ces groupes exceptionnellement nombreux.

Observational data from a 1-month study (November 1991) on a troop of Tanzanian black colobus, Colobus angolensis palliatus Peters, 1868, are presented. The troop inhabits an area of dry semi-evergreen forest in the eastern portion of the Gendagenda South Forest Reserve, Tanzania, which is subject to a bimodal seasonal climate. We show that during a period at the end of the dry season, the troop spent significantly more time feeding at the expense of resting, had a higher dietary diversity and ranged over a much greater area than during a period at the beginning of the wet season.

82. Angolan Colobus Colobus angolensis French: Colobe d'Angola / German: Angola-Stummelaffe / Spanish: Colobo de Angola Other common names: Angola Colobus, Angolan Black-and-white Colobus; Adolf Friedrich’s Angolan/Ruwenzori Black-and-white Colobus (ruwenzorii), Cordier’'s Angolan Colobus (cordieri), Peters’'s Angolan/Tanzanian Black-andwhite Colobus (palliatus), Powell-Cotton’s Angolan Colobus (cottoni), Prigogine’s Angolan/Prigogine’s Black-and-white Colobus (prigoginel), Sclater's Angolan Colobus (angolensis), Sharpe’s/Southern Highlands Angolan Colobus (sharpe)) Taxonomy. Colobus angolensis Sclater, 1860, Angola, 300 miles (483 km) inland from Bembe. In 2001, C. P. Groves recognized all of the named subspecies listed here except for sharper, which he believed to be a junior synonym of palliatus. C. sharpei was considered a valid subspecies of C. angolensis by U. Rahm in 1970, J. Kingdon in his 1971 review of East African primates, and P. Napier in 1985. In 1981, W. Rodgers provided information on the distributions of palliatus and sharpei that showed they were not isolated as they were thought to be and suggested they were not distinct taxa. Nevertheless, a molecular genetic study of palliatus across its distribution by M. McDonald and H. Hamilton in 2010 demonstrated distinct haplotypes in Kenyan and Tanzanian populations, which, combined with pelage differences highlighted by Rahm, Napier, and Kingdon, supported the validity of sharpei in central and southern Tanzania as a subspecies distinct from palliatus in Kenya. The form prigogine: could be synonymous with cordieri, but it is recognized as a subspecies of C. angolensis here. An unnamed subspecies of C. angolensis, the “Nkungwe’s Angolan Colobus ” or “Mahale Mountains Angola Colobus ” was listed by Groves in 2001 and P. Grubb and colleagues in their taxonomic review in 2003. It is an isolated population reported by T. Nishida and colleagues in 1981 from Mount Nkwunge and ridges of the northern Mahale Mountains as far as Mount Pasagula to the north and Mount Kahoko and Mount Sibindi to the south. It wasillustrated and described in a field guide of primates of the Mahale Mountains by T. Butynski and Y. de Jong in 2009, but it remains without a formal scientific trinomial. Seven subspecies recognized. Subspecies and Distribution. C.a.angolensisSclater,1860—DRCongo(SofthegreatbendoftheCongoRiver),NEAngola,andNWZambia,Stoc.12°SandWto¢.16°E. C.a.cordier:Rahm,1959—EDRCongoWoftheLualabaRiver,betweentheLowaandLuamariverstoclosetoLakeKivuintheEat¢.28°E(whereithybridizeswiththesubspeciesruwenzorii),andtothehighlandsWofLakeTanganyika,whereitextendstoc.6°S. C.a.cotton:Lydekker,1905—NEDRCongoEoftheCongo-L.ualabariversystem,fromtheNbankoftheCongoRiver(c.20°E)NtotheUeleRiver,EtoLakeAlbert,andStotheLindiRiver;formsahybridzonewiththesubspeciesruwenzoriiintheSofitsdistribution. C.a.palliatusPeters,1868—SEKenyaandNETanzania. C.a.prigogineiVerheyen,1959—EDRCongo(MtKabobo). C.a.ruwenzoriiThomas,1901—SEDRCongo,SEUganda,WRwanda,WBurundi,andNWTanzania;alongbothsidesoftheWRift,fromtheSemlikiValley,theRuwenzoriMts,andMtKahuzitotheshoresofLakeTanganyika. C. a. sharpei Thomas, 1902 — C & S Tanzania (as far W as Lake Rukwa), N Malawi, NW Zambia, and possibly occurring in N Mozambique. Descriptive notes. Head—body 55-66 cm (males) and 48-59 cm (females), tail 76 92 cm (males) and 63-76 cm (females); weight 7.6-12.6 kg (males) and 6.4-9.2 kg (females). The Angolan Colobus is generally black and characterized by long white epaulettes on shoulders and fluffy white circumfacial hair, the latter forming laterally elongated tufts on cheeks that resolve into a crescent shape. Tail may be tufted in males (not tufted in females), with varying extents of white (sometimes entirely white or with white restricted to the tuft). Two subspecies groups are recognized. The first is characterized by large epaulettes and a white pubic band (“Sclater’s Angolan Colobus,” C. a. angolensis; “Peters’s Angolan Colobus,” C. a. palliatus; “Adolf Friedrich’s Angolan Colobus,” C. a. ruwenzorii; and “Sharpe’s Angolan Colobus,” C. a. sharper). The other subspecies group has thin epaulettes and no white band on the pubic region (“Cordier’s Angolan Colobus,” C. a. cordieri; “Powell-Cotton’s Angolan Colobus,” C. a. cottons; and “Prigogine’s Angolan Colobus,” C. a. prigoginei). These two subspecies groups are linked by the unnamed Nkungwe Angolan Colobus that has well-developed epaulettes but lacks forehead and pubic bands. It is possible that some or all described subspecies may be distinct species. Sharpe’s Angolan Colobus is notable for its particularly long epaulettes, extending to its forearms, and bushy white side-whiskers. Prigogine’s Angolan Colobus has the smallest epaulettes and relatively reduced white side-whiskers. Habitat. A variety of forest types, from primary and secondary lowland rainforest and gallery forest to montane forest up to elevations of 3000 m and as high as 4000 m on Mount Ruwenzori. Although Angolan Colobus prefer the very highest levels of the forest canopy, including emergent trees, individuals will occasionally descend to the ground near streams to feed upon herbaceous vegetation. Food and Feeding. Diets of Angolan Colobus are mainly young leaves, along with shoots, seeds, unripe fruit, mature leaves, flowers, lichen, and termite clay. Water is obtained primarily from their food. Breeding. Female Angolan Colobus do not display a sexual swelling during the periovulatory period, and there is no perineal organ in the male. There is a definite birth season (May-December) in at least part of its distribution. A single young is born. The Natal coat is white, gradually changing through gray to black during the first six months. Activity patterns. The Angolan Colobus is diurnal and arboreal. At Nyungwe in Rwanda, its activity budget is 42% feeding, 32% resting, 20% moving, 5% engaging in social behavior, and 1% other activities. This population has unusually large group sizes (over 300 individuals), which may explain unusually high amounts of time spent feeding and moving and a relatively small amount of time devoted to resting, especially for a colobine. In a study in the Ituri forest of the DR Congo, groups of Angolan Colobus rested 43% of their time, fed 27%, moved 24%, engaged in social behavior 5%, and showed other behaviors 1%. Movements, Home range and Social organization. Daily movement has been reported at 983 m, with a home range of 371 ha. The Angolan Colobus generally lives in small family groups of 3—4 individuals, with a single male present. These family groups often form “troops” of up to 25-30 individuals, in which more than one male is present. One population in Rwanda (Nyungwe Forest) is exceptional in having a troop of more than 300 individuals, using a 2440ha home range. Little is known about the dispersal patterns of Angolan Colobus. Status and Conservation. CITES Appendix II. Classified as Least Concern on The IUCN Red List. The subspecies prigoginei is classified as Endangered, ruwenzorii as Vulnerable, cordieri as Near Threatened, and angolensis, cottoni, palliatus, and sharpei (under C. a. palliatus) as Least Concern. The undescribed Nkungwe taxon has not been assessed, but it is believed to be threatened. The Angolan Colobusis listed as Class B in the African Convention on the Conservation of Nature and Natural Resources. Although threatened in some parts ofits distribution (particularly in East Africa and the Albertine Rift), it remains widespread and relatively common in suitable habitat. Deforestation for timber and conversion of land for agricultural use are major threats, and isolated populations such as those in the Eastern Arc and coastal forests are especially vulnerable. It is also hunted for meat, especially in the Congo Basin. Populations in the eastern part ofits distribution are much more fragmented than those across the Congo Basin. The wide-ranging nominate form (Sclater’s Angolan Colobus) is known to occur in Salonga National Park in DR Congo and Mweru Wantipa National Park in Zambia. Peters’s Angolan Colobus occurs in isolated forests in south-eastern Kenya, restricted to the southern coastal forests of the Kwale District; a comprehensive survey located 55 populations. Although locally threatened from habitat loss and hunting in some parts of its highly fragmented distribution, Peters’s Angolan Colobus remains widespread and relatively common. The total population is estimated at 3100-5000 individuals (560-900 groups), with the population in Shimba Hills Forest Reserve being the largest at ¢.2400 individuals (c.15 ind/km?). Sharpe’s Angolan Colobus is likewise discontinuously distributed in forest patches in the Southern Highlands and coastal and gallery forests of southern and eastern Tanzania. It occurs in Udzungwa Mountains National Park and Gendagenda South Forest Reserve. Cordier’s Angolan Colobus has declined as a result of increased hunting. It is not known whether it occurs in any protected areas. Powell-Cotton’s Angolan Colobus is locally threatened from habitat loss and hunting in some parts ofits distribution but remains widespread. It occurs in Kahuzi-Biéga National Park, Virunga National Park, and Tayna Gorilla Reserve in DR Congo. Prigogine’s Angolan Colobus is confined entirely to Mount Kabobo in eastern DR Congo, where it is at continuing risk of habitat loss from agricultural expansion and hunting. It is not known whether it occurs in any protected areas. Adolf Friedrich’s Angolan Colobus is restricted to a few sites in the Albertine Rift region, where its habitat is fragmented and at risk from continued degradation. Hunting is also a threat. It occurs in Ruwenzori National Park in Uganda, Nyungwe Forest National Park in Rwanda, Kaya Gonja Nature Reserve in Kenya, and Mahale Mountains National Park in Tanzania. Bibliography. Anderson, Cowlishaw & Rowcliffe (2007), Anderson, Rowcliffe & Cowlishaw (2007), Ansell (1959), Butynski & de Jong (2009), Fashing (2011), Fashing, Mulindahabi et al. (2007), Fimbel et al. (2001), Groves (1973, 2001, 2007b), Kanga & Heidi (1999/2000), Kingdon (1971, 1997), McDonald & Hamilton (2010), Moreno-Black & Bent (1982), Napier (1985), Nishida et al. (1981), Rahm (1970), Rodgers (1981), Verheyen (1959)., Published as part of Russell A. Mittermeier, Anthony B. Rylands & Don E. Wilson, 2013, Cercopithecidae, pp. 550-755 in Handbook of the Mammals of the World – Volume 3 Primates, Barcelona :Lynx Edicions on page 699, DOI: 10.5281/zenodo.6867065

We considered the relationship between dental sexual dimorphism and diet in 542 specimens of olive, red, and black-and-white colobus. Using univariate statistical techniques, we examined 41 measurements of the maxillary and mandibular dentitions. The results reveal two trends of dental sexual dimorphism in black-and-white colobus wherein (i) maleColobus guereza andC. angolensis are generally larger than females throughout the dentition and (ii)C. satanas and, to a lesser degree,C. polykomos exhibit reduced sexual differences in the canine base and females are slightly larger than males in noncanine dimensions. Females of the red colobus,Procolobus (Piliocolobus) badius, are slightly larger than males in most noncanine measurements but canine sex differences are more pronounced than those of black-and-white colobus.Procolobus (Procolobus) verus, the olive colobus, is characterized by some of the largest canine sex differences, yet the sexes do not differ much in noncanine mean values. When patterns of sexual dimorphism are considered in terms of specific ecology and behavior, it is possible to relate sex differences, in part, to known dietary differences. For example, overall dental morphology and the trend of sexual differences inC. satanas andC. polykomos seem to be associated with the consumption of a diet rich in seeds. The pattern of dental sexual dimorphism inC. badius may also be influenced by dietary factors in that their patrilineal social organization could restrict female access to certain foods thereby affecting rates of attrition and creating selection pressure for larger teeth. Relatively less is known of the ecology and social organization ofP. verus but their dental sexual dimorphism is possibly less related to dietary factors than is the case for red or black-and-white colobus.

A group of Colobus polykomosat Tiwai, Sierra Leone, demonstrated seasonal flexibility in its diet, with seeds, young leaves, and mature leaves each dominating the diet at different times. Comparison of food consumption with phenological data indicates that seeds are eaten whenever available and are preferred to other foods, while young leaves are preferred to mature leaves. Colobus polykomosalso prefer liane to tree leaves, despite the relatively high quality of mature tree foliage at the Tiwai site. Analysis of protein, fiber, and energy values of foods selected and items available, but not eaten, suggests that preference is related to protein and energy maximization. Leguminous plants, especially Papilionaceae and Mimosaceae, are highlighted as important food sources for C. polykomos;seeds and leaves from these families have a high nitrogen content, and the protein content of leguminous seeds often equals or exceeds that found in leaves. It is predicted, therefore, that colobines living in habitats with a high density of legumes will feed heavily on seeds, subject to constraints such as seasonal availability. Where suitable leguminous species are less common, a mixture of fruits, seeds, and young or mature leaves or both is likely to be selected. The results of this and other recent studies of colobines do not support the notion that colobines are specialist folivores.

This paper reports preliminary data on a number of poorly known cercopithecids inhabiting the Lomako Forest, Zaire. Data include those on density, biomass, group size, the relationship between group type (mono vs. polyspecific) and forest type (mixed primary, secondary, monodominant primary, and swamp), and vertical stratification. Species examined are Colobus angolensis, Cercocebus aterrimus, Cercopithecus wolfi, Cercopithecus ascanius, Cercopithecus neglectus, and Allenopithecus nigroviridis. The density and biomass for the Lomako Forest anthropoids (excluding Cercopithecus neglectus and A. nigroviridis) are 165 ind/km2 and 1,034 kg/km2, respectively. Cercopithecus wolfi and Colobus angolensis are found in group sizes similar to those reported from other sites while Cercopithecus ascanius, Cercocebus aterrimus, and A. nigroviridis display group sizes unique to the Lomako. While Colobus angolensis, Cercocebus aterrimus, Cercopithecus ascanius and Cercopithecus wolfi were found, to varying extents, in all four forest types, Cercopithecus neglectus and A. nigroviridis inhabited only swamp forest. The different species sort out along vertical continua both within and between the four forest types. © 1994 Wiley-Liss, Inc.

For the first time, three cases of capture and forced interaction were observed between bonobos (Pan paniscus)and two other species of primates (Colobus angolensisand Cercopithecus ascanius)in the Lilungu (Ikela) region, Republic of Zaire. The bonobos interacted with the captured primates as if they were dealing with individuals of their own species. They sought cooperation in their interactions with the captured young primates without scccess. There is no evidence that they ate the captives.

Little is known about genetic variation in the 6–8 subspecies of Colobus angolensis, currently distinguished by pelage differences. We present a comparative genetic analysis of one of these subspecies, C. a. palliatus, in Kenya and Tanzania that assesses evolutionary relationships and patterns of mitochondrial genetic diversity in 103 individuals across its geographic range. Fecal samples from approximately 156 individuals were collected in four localities: (1) Diani Forest, Kenya; (2) Shimoni, Kenya; (3) Udzungwa Mountains National Park, Eastern Arc Mountains, Tanzania; and (4) Mount Rungwe, Southern Highlands, Tanzania. These samples represent at least six groups, with 5–15 samples from each. Comparative sequence analysis of a 1,795 base pair mtDNA fragment revealed 19 unique haplotypes in four populations. Phylogenetic analyses suggest that sampled Kenyan haplotypes are paraphyletic, with one Kenyan haplotype basal to all other sampled haplotypes. Analysis of molecular variance (AMOVA) suggests high levels of genetic variation among populations (ΦST 0.72, P