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The Red, Green and Blue (RGB) colour model has been used to investigate relationships between primates' physiological and colour data. This study uses the RGB method to determine various pelage hues in white-thighed surili at different latitudes in Peninsular Malaysia. Universiti Kebangsaan Malaysia (UKM) represents the lowland while Genting Highlands and Fraser’s Hill represent the highland area. Results indicated that no significant values were found based on the sample t-test on every section of the samples except on the nose (Green). Our findings can be utilised further for systematic and population genetic studies of Presbytis siamensis siamensis in Peninsular Malaysia. [ABSTRACT FROM AUTHOR]

Studies in multiple host species have shown that gut microbial diversity and composition change during pregnancy and lactation. However, the specific mechanisms underlying these shifts are not well understood. Here, we use longitudinal data from wild Phayre's leaf monkeys to test the hypothesis that fluctuations in reproductive hormone concentrations contribute to gut microbial shifts during pregnancy. We described the microbial taxonomic composition of 91 fecal samples from 15 females (n = 16 cycling, n = 36 pregnant, n = 39 lactating) using 16S rRNA gene amplicon sequencing and assessed whether the resulting data were better explained by overall reproductive stage or by fecal estrogen (fE) and progesterone (fP) concentrations. Our results indicate that while overall reproductive stage affected gut microbiome composition, the observed patterns were driven by reproductive hormones. Females had lower gut microbial diversity during pregnancy and fP concentrations were negatively correlated with diversity. Additionally, fP concentrations predicted both unweighted and weighted UniFrac distances, while reproductive state only predicted unweighted UniFrac distances. Seasonality (rainfall and periods of phytoprogestin consumption) additionally influenced gut microbial diversity and composition. Our results indicate that reproductive hormones, specifically progestagens, contribute to the shifts in the gut microbiome during pregnancy and lactation. [ABSTRACT FROM AUTHOR]

A significant number of Southeast Asian mammal species described in the 19th and 20th century were subsequently synonymized and are now considered subspecies. Many are affected by rapid habitat loss which creates an urgent need to re-assess the conservation status based on species boundaries established with molecular data. However, such data are lacking and difficult to obtain for many populations and subspecies. We document via a literature survey and empirical study how shotgun sequencing of faecal DNA is a still underutilized but powerful tool for accelerating such evaluations. We obtain 11 mitochondrial genomes for three subspecies in the langur genus Presbytis through shotgun sequencing of faecal DNA (P. femoralis femoralis, P. f. percura, P. siamensis cf. cana). The genomes support the resurrection of all three subspecies to species based on multiple species delimitation algorithms (PTP, ABGD, Objective Clustering) applied to a dataset covering 40 species and 43 subspecies of Asian colobines. For two of the newly recognized species (P. femoralis, P. percura), the results lead to an immediate change in IUCN status to Critically Endangered due to small population sizes and fragmented habitats. We conclude that faecal DNA should be more widely used for clarifying species boundaries in endangered mammals. [ABSTRACT FROM AUTHOR]

Abstract: Despite the growing literature on the underlying factors of geographical phenotypic variation, little is known about how and to what extent biogeographic barriers in South‐East Asia have shaped morphological variation in primates. We aimed to investigate the geographical variations in skull morphology in dusky leaf monkeys by decomposing them into clinal (latitudinal), non‐clinal spatial (discrete difference between regions north and south of the Isthmus of Kra), and environment‐related components. We applied geometric morphometrics to measure 53 adult male specimens from 36 localities, covering the regions both north and south of the Isthmus of Kra. A linear model was used to test the effects of region (north vs. south of the Isthmus of Kra), latitude, and environmental factors (temperature and rainfall) on the size and shape of skulls. A part of variation in skull shape differed moderately between the regions in the north and south of the Isthmus of Kra, and this difference cannot be explained by latitudinal and environmental factors. However, for size and the majority of variations in shape, we detected limited contributions of region and the two environmental factors. Shape differentiation that was unexplained by latitudinal and environmental factors suggests that dusky leaf monkeys may have experienced a population division due to habitat constriction around the Isthmus of Kra. However, this divergence probably has been obscured by subsequent gene flow between populations after habitat recovery. [ABSTRACT FROM AUTHOR]

Surili Sumatera (Presbytis melalophos ssp. mitrata Eschsholtz, 1821) is a primate species commonly found in Sumatra and Kalimantan. The subspecies of mitrata are known to be found along the Batanghari River, to the Geopark Mengkarang Purba area. However, data on the number of species in their habitat in Geopark Mengkarang Purba is not yet available. Thus, research on the demographics of riparian populations in riparian areas and the diversity of tree species as a residential habitat in the region is required. The data of this study were collected for ± 3 months in the Merangin Geopark area, West Bangko district in Bedeng Rejo and Rengas Ulu Villages. Geographically this location is located at 02o10'43.9 "LS, 102o10'47,5" BT with wavy topography. All aspects of population demographics were observed with transect strip technique on the 1.000 x 100 meter line for 10 repetitions per day. The number of paths observed was 3 lines representing the sampling intensity of 0,48% of the total area of the study site. The results showed that the total population of Sumatran Surili found in Geopark Mengkarang Purba area was 29 individuals with sex ratio of 1:2 and age structure which was considered progressive for the growth of Surili Sumatera population in Purba Geopark Mengkarang. The level of tree species diversity found in 31 species at the study site is close to high (H '= 2,96), most of which are found as fruit trees useful for the life and development of the Sumatran surili population. [ABSTRACT FROM AUTHOR]

This study highlights the daily activity budget of Silver leaf monkey at Kuala Selangor Nature Park. We followed a semi-habituated group (24 individuals) that lives inside the park for seven days/month for 12 months starting January 2014. Observation was conducted between 0700 hr and 1800 hr with 10 minutes of scanning time with a five minutes interval between observations. The results suggest that the Silvered leaf monkeys spent most of their times resting (55.73%), followed by feeding (20.55%), moving (14.18%), autogrooming (8.69%), allogrooming (2.06%), vocalization (1.01%), and agonistic interaction (0.41%). They also spent most of their times in the top and middle canopy with the percentage of 40% and 39% respectively. The findings can be used as a reference for future behavioral study in KSNP and also help to facilitate the species management and conservation effort in general. [ABSTRACT FROM AUTHOR]

Indonesia has amongst the highest primate species richness, and many species are included on the country's protected species list, partially to prevent over-exploitation. Nevertheless traders continue to sell primates in open wildlife markets especially on the islands of Java and Bali. We surveyed 13 wildlife markets in 2012-2014 and combined our results with previous surveys from 1990-2009 into a 122-survey dataset with 2,424 records of 17 species. These data showed that the diversity of species in trade decreased over time, shifting from rare rainforest-dwelling primates traded alongside more widespread species that are not confined to forest to the latter type only. In the 1990s and early 2000s orangutans, gibbons and langurs were commonly traded alongside macaques and slow lorises but in the last decade macaques and slow lorises comprised the bulk of the trade. In 2012-2014 we monitored six wildlife markets in Jakarta, Bandung and Garut (all on Java), and Denpasar (Bali). During 51 surveys we recorded 1,272 primates of eight species. Traders offered long-tailed macaque (total 1,007 individuals) and three species of slow loris (228 individuals) in five of the six markets, whereas they traded ebony langurs (18 individuals), and pig-tailed macaques (14 individuals) mostly in Jakarta. Pramuka and Jatinegara markets, both in Jakarta, stood out as important hubs for the primate trade, with a clear shift in importance over time from the former to the latter. Slow lorises, orangutans, gibbons and some langurs are protected under Indonesian law, which prohibits all trade in them; of these protected species, only the slow lorises remained common in trade throughout the 25-year period. Trade in non-protected macaques and langurs is subject to strict regulations-which market traders did not follow-making all the market trade in primates that we observed illegal. Trade poses a substantial threat to Indonesian primates, and without enforcement, the sheer volume of trade may mean that species of Least Concern or Near Threatened may rapidly decline. Am. J. Primatol. 79:e22517, 2017. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

In group-living mammals, social dominance can be achieved and maintained via kin support, winner–loser effects and individual differences in resource-holding potential (RHP). When dominance is based on RHP, the likelihood of winning is also influenced by the incentive to compete. For females, this equation can be quite complex, as both age and reproductive state can alter the relative value of resources and the risks associated with fighting. For example, females that are young, pregnant or lactating may have high nutritional demands, while lactating females also face risks associated with offspring survival. To date, however, there have been few studies investigating how such factors influence female agonistic relationships. Here, we use 2 years of data to evaluate how age and reproductive state influence the probability of winning, focusing on two groups (5–9 and 10–12 females) of wild Phayre's leaf monkeys, Trachypithecus phayrei crepusculus , at Phu Khieo Wildlife Sanctuary, Thailand. Consistent with previous studies, we found that young females and pregnant females were more likely to win dyadic interactions in the smaller group, PA. By contrast, the likelihood of winning was unrelated to age in the larger group, PB. Moreover, differences between reproductive states were less pronounced in PB, with females that were pregnant or in early lactation being more likely to win compared to females that were cycling. The deviating results for PB were likely associated with a greater number of competitors and small age differences intensifying intrasexual competition. These results highlight the importance of individual as well as demographic factors in female dominance relationships. In this population, females with high nutritional demands are more likely to win agonistic encounters, suggesting that female–female competition occurs primarily over access to resources. [ABSTRACT FROM AUTHOR]

The article discusses research which designed two primer pairs for the Cyt b gene region of the mitochondrial DNA to be used in the extraction of DNA obtained from the museum dry skin specimens of primate Presbytis.

Anti-predatory interspecific communication is observed between cohabiting species, as well as between prey and predator to communicate detection of 'stealthy hunters'. Predator mobbing is an extension of this communication, with prey species approaching and investigating or harassing a predator. Sunda Clouded Leopard Neofelis diardi is a predicted predator of both Bornean White-bearded Gibbon Hylobates albibarbis and Maroon Langur Presbytis rubicunda in Sabangau Forest, Central Kalimantan, Indonesia. This study reports an event in which gibbons and langurs cooperated in mobbing a clouded leopard. During the event, observers noted that the known c. sixmonth- old gibbon infant was not with the family group. We explain and contextualise this event in terms of primate cooperation and predator mobbing, both of which are rarely observed phenomena. Further knowledge of these interspecific relationships may help us in creating conservation strategies. [ABSTRACT FROM AUTHOR]

It is important to clarify the roles of different types of foods in the diet of primates that switch to other foods as preferred food items become rare. Using red leaf monkeys ( Presbytis rubicunda) in Danum Valley, Borneo, as an example, we compare the availability and nutritional properties of young leaves and seeds, as well as the monkeys' feeding behavior, to examine food choice and how such choices may affect their competitive regime. Over 21 mo, the number of flushing trees was larger than that of fruiting trees. When we compared nutritional content for all species, including those that the monkeys did not eat, seeds contained more lipids than young leaves but young leaves did not have any nutritional advantage over seeds. However, when we compared only food species, young leaves contained more crude ash than seeds. The proportion of food species to the total available species was significantly higher for seeds than for young leaves. In addition, red leaf monkeys selected young leaf species with higher digestible protein, but no nutritional component predicted seed selection. Young leaves are nutritionally low-quality in general, so monkeys may need to select species with higher quality leaves. However, seeds generally have high-quality nutritional values, so it may not be necessary to select species with marginally higher quality. When eating seeds, the number of individuals eating in the patch was larger, and this feeding in the patch tended to last longer than when monkeys ate young leaves, suggesting more intense feeding competition when feeding on seeds. In conclusion, seeds and young leaves have different nutritional advantages as foods and red leaf monkeys were more selective when eating young leaves than when eating seeds. [ABSTRACT FROM AUTHOR]

A correction to the article "Fallback Foods of Red Leaf Monkeys (Presbytis rubicunda) in Danum Valley, Borneo" by Goro Hanya and Henry Bernard in the previous issue is presented.

The marbled cat (Pardofelis marmorata) is arguably one of the least known Southeast Asian felids. Based mainly on indirect evidence, a nocturnal and predominantly arboreal lifestyle has been assumed while little is known about its diet. Here we report how a marbled cat injured a juvenile male Phayre's leaf monkey (Trachypithecus phayrei crepusculus; 33 months old) at the neck and shoulder within the Phu Khieo Wildlife Sanctuary, Thailand. The event suggests that this small cat may prey on individuals with a body mass exceeding its own and confirms that it can be active during early morning hours indicating a crepuscular-diurnal activity. There are also first indications that individual differences in monkey behaviour such as preferred feeding height, could influence predation risk. [ABSTRACT FROM AUTHOR]

Tropical rainforests on Borneo are rapidly shrinking due to human activities and related fires. Monitoring wildlife populations in their remaining habitats is crucial for developing effective conservation strategies. In 2012, we conducted surveys in Balikpapan Bay within the Sungai Wain forest, Indonesia, to estimate the population density of Maroon Langur Presbytis rubicunda (Müller, 1838). We surveyed Sungai Wain's primary core area using distance sampling of line transects, and assessed the vegetation structure using 100 m² square plots. We calculated density of P. rubicunda at 5.35 groups/km² (95% CI=3.4-8.43). Cluster size ranged between two and eight individuals and group size averaged 5.2 individuals (SE=1.4). The habitat within the core area of Sungai Wain appears suitable to support a high density of this colobine. Anthropogenic activities in the surrounding areas, as well as encroachment and illegal logging within the regenerating habitat, could become threats for P. rubicunda in Sungai Wain. This forest represents an important refuge for this primate in Balikpapan Bay. We recommend further surveys in degraded and regenerating forests to quantify the remaining suitable habitat for P. rubicunda in East Kalimantan. [ABSTRACT FROM AUTHOR]

Group-living primates enjoy numerous benefits, including effective resource defence from conspecifics in other groups. Resource contest often results in intergroup aggression, for which several hypotheses exist to explain its function: direct mate defence; direct food-resource defence; indirect food defence via 'hired guns'; mate attraction via infanticide, and indirect mate defence via male resource defence. I studied a focal group of Maroon Langurs Presbytis rubicunda in Sabangau tropical peatswamp forest and examined the nature of intergroup aggression. Evidence supported direct mate defence in the majority of intergroup encounters. However, given that the resources in this frugivorous population may be defensible, and that most intergroup encounters occurred within their 'core range' of valuable resources, it is likely that the females in the group benefited from indirect resource defence as a result of aggression by the male as a 'hired gun'. The focal group was the subject of a takeover by an invading male. The post-takeover home range and core range overlapped pre-takeover ranges by 75% and 43% respectively and post-takeover, the group reused 47% of sleeping trees (N=14), suggesting that the invading male established himself in the territory of the resident females, who then continued to use the resources therein. The focal group also fulfilled three criteria proposed to predict indirect mate defence via male resource defence in colobine monkeys. Thus, it appears that indirect mate defence may have been employed by the invading male to obtain reproductive access to females. This study represents the first preliminary evidence for both indirect-resource-defence-via-hired-guns and indirect-mate-defence-via-resource-defence hypotheses in the genus Presbytis. [ABSTRACT FROM AUTHOR]

ABSTRACT In primates and other mammals, weaning is an equivocal concept, as is reflected in the numerous ways it is measured: a) first intake of solid food, b) conflict over access to the nipple, c) ability to survive without mother, d) maternal resumption of cycling, or e) the cessation of nipple contact. The lack of a consistent definition means that weaning age, although it falls between gestation (fetal growth) and age at first reproduction (most energy diverted from growth), is currently not a reliable life history variable capturing offspring independence. Using data for wild Phayre's leaf monkeys ( Trachypithecus phayrei crepusculus) at Phu Khieo Wildlife Sanctuary, Thailand (51 offspring, four groups), we asked whether the end of nipple contact indicates offspring independence as measured by survival to 3 years. To establish a baseline for the onset of independence, we assessed the youngest age at which individuals were orphaned (15-17 months) but then survived to 3 years. Next we determined that offspring age at last nipple contact (19.0 months) was comparable to two other independently calculated measures: offspring age at mother's first postpartum ovulation (11.5 months), and age at mother's re-conception (15.6 months). Using these separate 'starting points,' we arrived at similar ages for nipple contact cessation (18.4 and 19.2 months, respectively). Overall, in wild (but not in provisioned) Asian colobines, age at last nipple contact was allometrically related to adult female body mass, supporting its designation as a life history variable. Future comparisons need to show if this holds for other taxa. Am J Phys Anthropol 154:291-301, 2014. © 2014 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Despite supporting the highest biodiversity on Earth, tropical rainforests are undergoing intensive economic development. In particular, the island of Borneo has lost over 56 % of original lowland forest to resource extraction, fires, and illegal logging. Its rainforests contain 16 primate species, which serve as excellent 'umbrella' taxa for conservation initiatives. The genus Presbytis (Colobinae) is well represented across Borneo by four endemic species ( P. chrysomelas; P. frontata; P. hosei, and P. rubicunda), but remains relatively understudied. Using ecological niche modelling, I calculated the distributions of the 12 Bornean Presbytis subspecies; evaluated habitat loss between 2000 and 2010, and examined the current land-use policies across remnant distributions. Subspecies experienced a mean 12.7 % (N = 12 sp.) habitat reduction over the 10 year period. 12.5 % of all habitats were allocated for conversion to oil palm and industrial tree plantations, while logging concessions accounted for a mean 26.3 % across distributions. While the current protected area networks encompassed an average 33.4 % of distributions, most PAs are underfunded, degraded and threatened by logging and mining operations. I therefore recommend priority gazetting of unallocated lands to new PAs within the distribution of Presbytis chrysomelas and Presbytis hosei sabana, which have experienced the highest forest loss in the last 10 years (22-50 %) and are critically endangered. Logging concessions appear to be at least as effective in maintaining forest cover as PAs and have the economic advantage for effective management, but may have detrimental effects to monkey populations. I recommend an urgent assessment of the effects of selective logging practices on species' persistence, and further recommend population surveys to quantify the populations of critically endangered and data deficient subspecies. [ABSTRACT FROM AUTHOR]

Knowledge of a species' ranging patterns is vital for understanding its behavioral ecology and vulnerability to extinction. Given the abundance and even distribution of leaves in forested habitats, folivorous primates generally spend less time feeding; more time resting; have shorter day ranges; and require smaller home ranges than frugivorous primates. To test the influence of frugivory on ranging behavior, we established the activity budget and home-range size and use in a highly frugivorous population of the Borneo-endemic colobine, Presbytis rubicunda, within Sabangau tropical peat-swamp forest, Central Kalimantan, and examined relationships between fruit availability and ranging patterns. We collected 6848 GPS locations and 10,702 instantaneous focal behavioral scans on a single group between January and December 2011. The group had the largest home-range size recorded in genus Presbytis (kernel density estimates: mean = 108.3 ± SD 3.8 ha, N = 4 bandwidths). The annual activity budget comprised 48 ± SD 4.0% resting; 29.3 ± SD 3.9% feeding, 14.2 ± SD 2.5% traveling, and 0.4 ± SD 0.4% social behaviors. Mean monthly day-range length was the highest recorded for any folivorous primate (1645 ± SD 220.5 m/d). No significant relationships existed between ranging variables and fruit availability, and ranging behaviors did not vary significantly across seasons, potentially owing to low fluctuations in fruit availability. Our results suggest that colobine monkeys maintain larger than average ranges when high-quality food resources are available. Their extensive range requirements imply that protecting large, contiguous tracts of habitat is crucial in future conservation planning for Presbytis rubicunda. [ABSTRACT FROM AUTHOR]

The whipworm of humans, Trichuris trichiura, is responsible for a neglected tropical disease (NTD) of major importance in tropical and subtropical countries of the world. Whipworms also infect animal hosts, including pigs, dogs and non-human primates, cause clinical disease (trichuriasis) similar to that of humans. Although Trichuris species are usually considered to be host specific, it is not clear whether non-human primates are infected with T. trichiura or other species. In the present study, we sequenced the complete mitochondrial (mt) genome as well as the first and second internal transcribed spacers (ITS-1 and ITS-2) of Trichuris from the François’ leaf-monkey (langur), and compared them with homologous sequences from human- and pig-derived Trichuris. In addition, sequence comparison of a conserved mt ribosomal gene among multiple individual whipworms revealed substantial nucleotide differences among these three host species but limited sequence variation within each of them. The molecular data indicate that the monkey-derived whipworm is a separate species from that of humans. Future work should focus on detailed population genetic and morphological studies (by electron microscopy) of whipworms from various non-humans primates and humans. [ABSTRACT FROM AUTHOR]

Diet and habitat overlaps were studied for the leaf monkey (Presbytis rubicunda) and bornean white-bearded gibbons (Hylobates albibarbis) in tropical forest of Cabang Panti Research Station (CPRS), Gunung Palung National Park, West Kalimantan. Systematic data on feeding and ranging behaviour were collected from August 2009 up to February 2010 for the three groups of two sympatric primate species that shared two neighbouring patches. Our results showed that seven types of habitat in CPRS were affected to both primates, particularly in plant utilization for feed and the use of vertical space patterns. If the leaf monkeys were present in the same forest patch, the Bornean white-bearded gibbons showed a reduced within-group dispersal and significantly less foraging time in a given forest patch. This might be due to the bornean white-bearded gibbons were more selective in their diet selection. When fruits were scarce, bornean white-bearded gibbons spent most of their foraging time in many types of forest ecosystem, while leaf monkey foraged within one or two types of forest ecosystem. At this period, diet and habitat overlaps between the two species were low. When the availability of fruits increased, leaf monkeys shifted their foraging range and both species became confined to the forest habitat. Consequently, the overlaps of diets and habitats were increased while the peak was at the end of the fruit season. [ABSTRACT FROM AUTHOR]

The banded leaf monkey (Presbytis femoralis femoralis) is critically endangered in Singapore and affected by widespread deforestation in southern Peninsular Malaysia. The Singapore population has recovered from a low of 15-20 to more than 40 individuals, but prior to our study it was unclear how severely the past bottleneck had depleted the genetic diversity of the population. Here, we provide the fi rst analysis of the genetic variability based on seven samples (ca. 20% of population) collected over two years of fi eldwork. We fi nd only two haplotypes that differ only in one variable site for the hypervariable region I (HV-I) of the mitochondrial d-loop. Compared to available population-level data for other colobines (proboscis monkey, Yunnan snub-nosed monkey, Sichuan snub-nosed monkey, Angolan black and white colobus), the banded leaf monkey population in Singapore has the lowest number and the most similar haplotypes. This low genetic variability is the next challenge for the conservation of the population. Protected habitats in prospering urban environment may become important sanctuaries for endangered species, but reintroductions may have to be considered in order to restore genetic variability that was lost during past bottlenecks. [ABSTRACT FROM AUTHOR]

Extended sexual receptivity in primates is thought to facilitate paternity confusion, thus decreasing the risk of infanticide. However, females might also provide some indication of ovulation to attract preferred males during fertile periods. We examined female mate preferences across defined receptive periods ( N = 59) in a group of wild Phayre's leaf monkeys ( Trachypithecus phayrei crepusculus) at Phu Khieo Wildlife Sanctuary (February-September 2006; 2,603 contact hours). The group contained seven cycling adult females and three reproductively active males (one adult and two adolescents). We predicted that females would prefer the adult male during periovulatory ( POP) receptive periods, but the adolescent males during nonperiovulatory ( NPOP) and postconceptive ( PC) periods. We collected focal and ad libitum data on sexual and agonistic behaviors to determine female preferences and male awareness of female fertility. We also determined the degree of mating overlap to assess if males were capable of monopolizing females. Our results indicate that females were more frequently proceptive and receptive toward the adult male during POP. By contrast, females were more proceptive and receptive toward one of the adolescent males during PC periods, but rarely interacted with the other adolescent. Patterns of attractivity and agonism across receptive periods suggested that the adult male could detect fertility, while the preferred adolescent could not. Finally, we found a high degree of overlap in total receptive period days, but a low degree of overlap in POP receptive days, suggesting that the adult male might have monopolized females, especially since he seemed to be aware of female fertility. Although these results suggest that females provide some information on ovulation, they also suggest that females attempt to confuse paternity, perhaps capitalizing on male differences in the ability to detect fertility. Am. J. Primatol. 74:471-481, 2012. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

According to ecological theory, the concept of niche differentiation is essential to our understanding of how sympatric species can limit competition over resources. We here examine ecological niche differentiation in 2 sympatric Asian langurs, Presbytis potenziani and Simias concolor, both endemic to the Mentawai Islands off the west coast of Sumatra. We collected data (home range size, canopy use, activity budgets, diet, and niche breadth and overlap) using GPS and scan/focal animal sampling methods on 2 groups of Presbytis potenziani and 3 groups of Simias concolor living in a mixed primary rain forest in northern Siberut. Results show that home ranges of the 2 species overlapped completely and that the home range size of Presbytis potenziani was ca. 4 times larger than that of Simias concolor. Lower canopy levels (<20 m) were used more often by Simias concolor, whereas Presbytis potenziani preferred the canopy >20 m. Apart from foraging and other activities, there was little difference in overall activity budgets of the 2 species. Regarding diet, although 60% of all food species examined were used by both langur species, they shared only 3 of the 10 most commonly eaten species. Presbytis potenziani fed more selectively on fruits, whereas Simias concolor fed predominantly on leaves. Levin's niche breadth indices revealed that the diet of Simias concolor is more general (0.34) than that of Presbytis potenziani (0.22). Based on a Pianka index of 0.32, we conclude that there is a relatively small food niche overlap between the 2 colobine species and that diet represents an important mechanism enabling their coexistence. [ABSTRACT FROM AUTHOR]

The article discuses how acoustic structure of male loud-calls support molecular phylogeny of Sumatran and Javanese leaf monkeys. Research is based on a field survey in 19 locations on Sumatra, Java and the Mentawai islands. The acoustic analysis of 100 surili male loud-calls from 68 wild animals confirms that the acoustic structure of surili loud-calls is a reliable tool to distinguish between species and to verify phylogenetic relatedness and migration backgrounds of respective taxa.

Infanticide by males is common in mammalian species such as primates in which lactation lasts much longer than gestation. It frequently occurs in one-male groups following male takeovers and is likely a male reproductive strategy. Reported female countertactics include abrupt weaning of infants, dispersal, or paternity confusion. Here, we estimated costs of female countertactics in terms of weaning ages and interbirth intervals. We observed a population of white-headed leaf monkeys ( Trachypithecus leucocephalus) in Nongguan Nature Reserve, China (1995-2006) mainly composed of one-male groups. Takeovers ( N = 11) coincided with the peak conception period. Detailed data are presented for five takeovers (34 females, 29 infants, and 47 group-years) leading to six infant disappearances (42.9% of infant mortality). All presumed infanticides were in accordance with the sexual selection hypothesis. Following a takeover, females without infants or with old infants stayed with the new males, incurring no or low costs (via abrupt weaning). Females with young infants dispersing with the old males also experienced low costs. High costs (due to infant loss) were incurred by pregnant females and those with young infants who stayed with the new males indicating that paternity was not confused. Costs in terms of long interbirth intervals were also high for females leaving with the old males to later join the new males, despite infant survival. Female countertactics reflected female philopatry mediated by infant age. Presumably due to the seasonal timing of takeovers, most countertactics seemed successful given that 32.3% of females apparently incurred no costs and 41.2% incurred only low costs. [ABSTRACT FROM AUTHOR]

Trachypithecus delacouri (Osgood, 1932), commonly called Delacour's langur or lutung, is a black and white lutung (leaf monkey) endemic to northern Vietnam. It is a diurnal and primarily arboreal species, but spends more time on the ground than other species of Trachypithecus. T. delacouri lives among limestone cliffs and consumes the leaves of a broad spectrum of plant species but its choice of food items tends to be based on the chemical makeup of the plant phenophases with protein content the strongest predictor of leaf selection. Territorial, but with overlapping territories, it usually lives in single- male--multifemale groups of 5-30, although 2 adult males may be present. With a declining population perhaps as low as 200 individuals in 17 or fewer isolated populations, it is 1 of the world's most endangered primates. [ABSTRACT FROM AUTHOR]

Lao leaf monkeys ( Trachypithecus ( francoisi) laotum) are endemic to a small area of central and, marginally, north Lao. They are known from a few, mostly vague, historical records. We here present a detailed examination of the distribution of this little-known taxon and discuss its conservation status. Surveys since 1992 show its range to be centered upon the karst-dominated Phou Hin Poun National Protected Area (NPA), Nam Sanam Provincial Protected Area, and the southern part of Nam Kading NPA. The known range encompasses <2000 km², within which occurrence is patchy, reflecting habitat availability. The taxonomic identity of leaf monkeys plausibly of this group reported to the north of this area is not known. In the south of Phou Hin Poun NPA, village reports that the monkeys have black heads are corroborated by the few sightings; their taxonomic relationship with typical Trachypithecus laotum is unknown. In the mid-late 1990s large populations remained and individuals were easily seen. There is no apparent large-scale threat to their habitat. There has been no significant reassessment of status since the late 1990s, nor is there any active conservation action in place. Although the monkeys are to a significant extent protected by the arduous terrain, this cannot be relied upon indefinitely: Trade-directed hunting, although apparently limited in the 1990s, is a potential threat that could cause rapid population declines. Local traditions offer significant starting points for conserving these monkeys. [ABSTRACT FROM AUTHOR]

Abstract: The langurs of the genus Presbytis inhabit tropical rainforests of Sundaland, and with more than 50 color variants grouped in up to eleven species, Presbytis is one of the most diverse Old World monkey genera. The number of taxa and their phylogenetic relationships however remain controversial. To address these issues, we analyzed a 1.8kb long fragment of the mitochondrial genome, including the cytochrome b gene, the hypervariable region I of the D-loop and the intermediate tRNAs, from individuals representing nine species. Based on our data, we obtained various well-supported terminal clades, which refer mainly to described taxa. Relationships among these clades are not fully resolved, suggesting at least two radiations in the evolutionary history of the genus. According to divergence age estimates, radiations occurred in the late Miocene and the early to middle Pleistocene. Our findings support the revision of the current classification of the genus Presbytis and enable us to discuss implications for conservation. However, further studies including nuclear sequence data are necessary to completely understand the evolutionary history of the genus, and to address possible hybridization events among taxa. [Copyright &y& Elsevier]

The predation pressure put on primates by diurnal birds of prey differs greatly between continents. Africa and South America have specialist raptors (e.g. crowned hawk-eagle Stephanoaetus coronatus and harpy eagle Harpia harpyja) whereas in Asia the only such specialist's (Philippine eagle Pithecophaga jefferyi) distribution is largely allopatric with primates. The almost universal absence of polyspecific groups in Asia (common in Africa and South America) may indicate reduced predation pressure. As such there is almost no information on predation pressures on primates in Asia by raptors. Here we report successful predation of a juvenile banded langur Presbytis femoralis (~2 kg) by a changeable hawk-eagle Spizaetus cirrhatus. The troop that was attacked displayed no signs of being alarmed, and no calls were made before the event. We argue that in insular Southeast Asia, especially, large Spizaetus hawk-eagles (~2 kg) are significant predators of arboreal colobines. Using data on the relative size of sympatric Spizaetus hawk-eagles and colobines we make predictions on where geographically we can expect the highest predation pressure (Thai-Malay Peninsula) and which colobines are least ( Nasalis larvatus, Trachypithecus auratus, P. thomasi) and most ( P. femoralis, T. cristatus) affected. [ABSTRACT FROM AUTHOR]

The physical growth patterns of crested langurs and vervet monkeys are investigated for several unilinear dimensions. Long bone lengths, trunk height, foot length, epiphyseal fusion of the long bones and the pelvis, and cranial capacity are compared through six dental growth stages in male Trachypithecus cristatus (crested langurs) and Cercopithecus aethiops (vervet monkeys). Results show that the body elements of crested langurs mature differently than those of vervets. In some dimensions, langurs and vervets grow comparably, in others vervets attain adult values in advance of crested langurs, and in one feature the langurs are accelerated. Several factors may explain this difference, including phylogeny, diet, ecology, and locomotion. This study proposes that locomotor requirements affect differences in somatic growth between the species. [ABSTRACT FROM AUTHOR]

Abstract: Female reproduction is known to be influenced by food availability and its impact on energetic status. However, emerging evidence suggests that the phytochemical content of food may also be an important factor. Here, we investigated this hypothesis, presenting 20months of data on fecal progestin (fP) patterns in wild female Phayre''s leaf monkeys (Trachypithecus phayrei crepusculus). We examined whether (a) the availability of Vitex (a plant known to contain phytochemicals) might be linked to seasonal fP levels, (b) fP levels were associated with female reproductive performance, and (c) reproductive performance might also be linked with energetic status (as measured by physical condition). We collected fecal samples (N =2077) from 10 adult females to analyze estrogen (fE) and progestin (fP) metabolites, behavioral data from 7 cycling females to determine receptivity, and monthly data on Vitex availability and female physical condition. Seasonally elevated fP levels were found in all females, with higher levels when Vitex leaves and fruits were abundant. During the period of high progestins, females had longer cycle lengths and follicular phases, while receptive periods did not change. Nevertheless, when ovulations occurred, females were more likely to conceive. On the other hand, conceptions were also more likely when physical condition was improving, suggesting that the effects of phytochemicals and energetic status on reproduction may be difficult to separate. Although our results support the predicted effects of Vitex on endocrine and reproductive function, future studies with detailed feeding data and chemical analyses of plants are needed to confirm this finding. [Copyright &y& Elsevier]

Numerous morphology-based classification schemes have been proposed for langurs and leaf monkeys of South Asia but there is very little agreement between them. An incorrect classification scheme when used as a basis for biogeographic studies can support erroneous hypotheses. Further, lack of taxonomic resolution will also confound conservation efforts, given that conservation biologists use traditional morphology-based-classification schemes to prioritize species for conservation. Here, I have revisited recent molecular phylogenetic studies done on langurs and leaf monkeys of South Asia. Results from these studies are in turn used to derive a rational and scientific basis for prioritizing species for conservation. Molecular data support the classification of langurs of the Indian subcontinent-Hanuman, Nilgiri and purple-faced langurs-in the genus Semnopithecus, whereas Phayre's leaf monkey along with other Southeast Asian leaf monkeys form another distinct clade (Trachypithecus). The phylogenetic position of capped and golden langurs remains unresolved. Molecular data suggest that they are closely related to each other but this group might have evolved through past hybridization between Semnopithecus and Trachypithecus. Additionally, genetic data also support the splitting of the so-called Hanuman langurs into at least three species. The scores for taxonomic uniqueness of langurs and leaf monkeys of South Asia were revised using this molecular phylogeny-based classification. According to the revised scores, Phayres leaf monkey and golden langur are priority species for conservation followed by capped and Nilgiri langurs. [ABSTRACT FROM AUTHOR]

Understanding female reproductive characteristics is important for assessing fertility, interpreting female behavior, and designing appropriate conservation and captive management plans. In primate species lacking morphological signs of receptivity, such as most colobines, determination of reproductive parameters depends on the analysis of reproductive hormones. Here, we use fecal hormone analysis to characterize cycle patterns ( N=6 females) and gestation length ( N=7 females) in a group of wild Phayre's leaf monkeys ( Trachypithecus phayrei crepusculus) in Phu Khieo Wildlife Sanctuary, Thailand. We found that both fecal estrogen (fE) and progestin (fP) levels showed clear biological patterns indicative of ovulation and conception. However, because fP patterns were inadequate in determining the end of the luteal phase, we used fE rather than fP patterns to delineate menstrual cycle parameters. We found a mean cycle length of 28.4 days ( N=10), with follicular and luteal phases of 15.4 ( N=10) and 12.5 days ( N=14), respectively. On average, females underwent 3.57 ( N=7) cycles until conception. Average gestation length was 205.3 days ( N=7), with fE levels increasing over the course of pregnancy. Overall, the reproductive characteristics found for Phayre's leaf monkeys were consistent with results for other colobine species, suggesting that fecal hormone monitoring, particularly for fE metabolites, can provide useful reproductive information for this species. Am. J. Primatol. 72:1073-1081, 2010. © 2010 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

The banded leaf monkey (Presbytis femoralis femoralis) is the largest extant non-human primate in Singapore and its population is known to be critically endangered and restricted to the Central Catchment Nature Reserve. Prior to this study it was uncertain whether the species is reproducing in Singapore and there were confl icting reports about infant colouration, casting doubts on whether the subspecies in Singapore is different from that in Johor, Malaysia. Here we present the first report on reproduction, infant pelage colouration and development of the banded leaf monkeys in Singapore based on 22 months of observational data. We report at least six births from 2008 to 2010, and present evidence that there is at least one birth season in June/July for three consecutive years. Moreover several infants have survived beyond seven months, implying low infant mortality. The infants are born white, with a black line from head, along the spine, to tail that is intersected by a black line passing along the shoulders to the outer surfaces of both forearms thus forming a distinctive cruciform (cross-like) black pattern on the dorsum. This natal pelage pattern is consistent with that of the banded leaf monkey infants in Johor, suggesting no differentiation between the two populations based on infant colouration. These data are preliminary and more long-term research is needed to understand the reproductive behaviour of this native and elusive primate in Singapore. [ABSTRACT FROM AUTHOR]

Trachypithecus cristatus (Raffles, 1821), silvered lutung, is a colobine monkey of the Malay Peninsula and Archipelago. It has a pointed crest and outward-projecting cheek hairs, and gray skin and pelage with some grayish white hairs that are lighter distally, giving a silvered appearance. Diurnal and arboreal, it runs and jumps quadrupedally, with limited semibrachiation. Its large stomach and foregut fermentation allow it to digest a diet with a high proportion of leaves. It lives in single male-multifemale groups and smaller multimale groups in a polygynous, cooperative-breeding mating system. As with other nonhuman primates, it is threatened throughout its range by logging, hunting for meat and medicinal uses, and capture for the pet trade. [ABSTRACT FROM AUTHOR]

The six limestone langur taxa of Southeast Asia inhabit the rugged limestone karst mountains, although the reason for their current restriction to this habitat is unclear. From August 2007 to July 2008, I collected data on the diet and feeding behavior of the critically endangered Delacour's langur (Trachypithecus delacouri) in Van Long Nature Reserve, Vietnam. I used these data to evaluate the hypothesis that limestone langurs are found on karst habitat because they depend on endemic limestone plants. Feeding accounted for 29% of the langurs' activity budget. Young leaves dominated the diet monthly, seasonally, and annually. The annual diet consists of nearly 79% foliage with almost 60% young leaves. Despite a distinct wet and dry season, over the study period, seasonal variation in plant part consumption was slight. Fruit and seeds were a small contribution to the diet. Delacour's langurs ate 42 of 145 available species, and they concentrated on a subset of this number. Five plant species comprised more than 60% of the diet and 16 species comprised more than 93%. More than half of the diet came from climbers. Delacour's langurs are among the most highly folivorous of studied colobines and, along with the closely related T. leucocephalus of southern China, the most folivorous of the Asian langurs. Whether high folivory is owing to a lack of available fruits and seeds in limestone habitats is unknown. What is certain, however, is that the plant species most important in the Delacour's langurs' diet at VLNR, throughout the study, were not plants endemic to limestone. Feeding dependence alone, therefore, cannot explain the current distribution of limestone langurs on karst habitat. Am. J. Primatol. 72:317–324, 2010. © 2009 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Within phylogenetic limits reproductive characteristics of a given species may vary between populations in response to ecological and social factors. For instance, in environments where high quality nutrition is readily available, the onset and speed of reproduction are often accelerated. Other influencing factors might be maternal experience or the sex of the infant. Here we present data on reproductive characteristics for the silvered leaf monkey (Trachypithecus cristatus), a medium-sized Asian colobine housed at the Wildlife Conservation Society's Bronx Zoo as a one-male group. To place the species into an appropriate phylogenetic context, we limited our comparison to other colobine species. Demographic data span 21.4 years (October 1985 to March 2007) and derive from 30 adult females (128.0 female years). Detailed behavioral data stem from a 2.2 years study (November 2002 to January 2005; 734 days, 4,225 hr). As in other Asian colobines, receptive periods were short (mean=4.3 days, n=68). This is expected for one-male groups where receptivity likely indicates, rather than conceals, ovulation. Gestation length was estimated based on a change in the pattern of sexual behavior (mean=194.6 days, n=7). It fell within the range reported for the taxon. Births occurred year round, at an early age (mean=2.9 years, n=8), at short intervals (mean=14.9 months, n=59) in combination with a short lactation (mean 12.1 months, n=9) likely due to the nearly unlimited availability of nutrition in this zoo setting. Primiparous females tended to have a longer first interbirth interval but infant survival rates were similar to multipara possibly due to the absence of predators. Maternal investment was independent of the infant's sex and birth sex ratio was even. Our results emphasize that when interpreted with caution, zoo populations yield realistic reproductive characteristics that can help fill the gap in our knowledge about colobine life history. Am. J. Primatol. 71:852–859, 2009. © 2009 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

A recent phylogenetic study of langurs and leaf monkeys of South Asia suggested a reticulate evolution of capped and golden leaf monkeys through ancient hybridization between Semnopithecus and Trachypithecus. To test this hybridization scenario, I analysed nuclear copies of the mitochondrial cytochrome b gene (numts) from capped, golden and Phayre's leaf monkeys. These numts were aligned with mitochondrial cytochrome b sequences of various species belonging to the genera Semnopithecus and Trachypithecus. In the phylogenetic tree derived from this alignment, the numts fell into three distinct clades (A, B and C) suggesting three independent integration events. Clade A was basal to Semnopithecus, and clades B and C were basal to Trachypithecus. Among the numts in clades A and C were sequences derived from species not represented in their respective sister mitochondrial groups. This unusual placement of certain numts is taken as additional support for the hybridization scenario. Based on the molecular dating of these integration events, hybridization is estimated to have occurred around 7.1 to 3.4 million years ago. Capped and golden leaf monkeys might have to be assigned to a new genus to reconcile their unique evolutionary history. Additionally, northeast India appears to be a 'hot spot' for lineages that might have evolved through reticulate evolution. [ABSTRACT FROM AUTHOR]

Primate population assessments provide the basis for comparative studies and are necessary prerequisites in determining conservation status. The most widely used assessment method is line transect sampling, which generates systematic data quickly and comparatively inexpensively. In contrast, the presumably most reliable method is long-term monitoring of known groups, which is both slow and costly. To assess the reliability of various analytical methods, we compared group and population densities for white-handed gibbons ( Hylobates lar carpenteri) and Phayre’s leaf monkeys ( Trachypithecus phayrei crepusculus) derived from transect walks with those from long-term group follows at Phu Khieo Wildlife Sanctuary, Thailand. Our assistants and we regularly walked a 4-km transect over 30 mo (480 km total), resulting in 155 gibbon sightings and 125 leaf monkey sightings. We then estimated densities via 1) DISTANCE and 2) the Kelker method based on perpendicular distances (PD) or animal-to-observer distances (AOD). We compared the 3 estimates to values based on known home ranges (95% kernels), accounting for home range overlap, combined with group size data. Analyses of line transect data consistently overestimated group densities for both species, while underestimating group size for leaf monkeys. Quality of results varied according to the group size and spread of each species. However, we found, in accordance with previous studies, that values derived via AOD (or its derivations) matched most closely with population estimates based on home range data. [ABSTRACT FROM AUTHOR]

The loud calls nonhuman primates use in long-distance communication have supposedly been selected for efficient information transfer in the habitat. The differential effects of scattering and reverberation and the masking effects of background noise predict that loud calls produced in rain forest habitats should be low-pitched and whistle-like with low-frequency modulation. Callers may also use particular calling posts or times of day with reduced background noise to increase the efficacy of sound transmission. We studied the loud calls of the 4 sympatric primate species on Siberut Island. Only Kloss gibbons ( Hylobates klossii) fulfilled the predictions regarding both the structure and use of calls. Though the other 3 species —Mentawai macaques ( Macaca siberu), pig-tailed langurs ( Simias concolor), and Mentawai leaf monkeys ( Presbytis potenziani)— also concentrated their main energies in the spectral window with the lowest background noise, their calls were not adapted to long-range transmission. All 4 species produced loud calls exclusively no lower than 18 m above ground, but food abundance and shelter in the canopy may also be factors. Though all 4 species produced the majority of loud calls in the morning, it was not the only time of day with reduced background noise. We suggest that phylogenetic inheritance may better explain the structure of calls than adaptation to the habitat. In sum, the observed usage of spectral and temporal niches is not solely an adaptation to the sound profile of the habitat, though it clearly improves their transmission. [ABSTRACT FROM AUTHOR]

Background: The evolutionary history of the Asian colobines is less understood. Although monophyly of the odd-nosed monkeys was recently confirmed, the relationships among the langur genera Presbytis, Semnopithecus and Trachypithecus and their position among Asian colobines remained unclear. Moreover, in Trachypithecus various species groups are recognized, but their affiliations are still disputed. To address these issues, mitochondrial and Y chromosomal sequence data were phylogenetically related and combined with presence/absence analyses of retroposon integrations. Results: The analysed 5 kb fragment of the mitochondrial genome allows no resolution of the phylogenetic relationships among langur genera, but five retroposon integrations were detected which link Trachypithecus and Semnopithecus. According to Y chromosomal data and a 573 bp fragment of the mitochondrial cytochrome b gene, a common origin of the species groups T. [cristatus], T. [obscurus] and T. [francoisi] and their reciprocal monophyly is supported, which is also underpinned by an orthologous retroposon insertion. T. [vetulus] clusters within Semnopithecus, which is confirmed by two retroposon integrations. Moreover, this species group is paraphyletic, with T. vetulus forming a clade with the Sri Lankan, and T. johnii with the South Indian form of S. entellus. Incongruence between gene trees was detected for T. [pileatus], in that Y chromosomal data link it with T. [cristatus], T. [obscurus] and T. [francoisi], whereas mitochondrial data affiliates it with the Semnopithecus clade. Conclusion: Neither relationships among the three langur genera nor their position within Asian colobines can be settled with 5 kb mitochondrial sequence data, but retroposon integrations confirm at least a common origin of Semnopithecus and Trachypithecus. According to Y chromosomal and 573 bp mitochondrial sequence data, T. [cristatus], T. [obscurus] and T. [francoisi] represent true members of the genus Trachypithecus, whereas T. [vetulus] clusters within Semnopithecus. Due to paraphyly of T. [vetulus] and polyphyly of Semnopithecus, a split of the genus into three species groups (S. entellus - North India, S. entellus - South India + T. johnii, S. entellus - Sri Lanka + T. vetulus) seems to be appropriate. T. [pileatus] posses an intermediate position between both genera, indicating that the species group might be the result of ancestral hybridization. [ABSTRACT FROM AUTHOR]

Primates give alarm calls in response to the presence of predators. In some species, such as the Thomas langur (Presbytis thomasi), males only emit alarm calls if there is an audience. An unanswered question is whether the audience's behaviour influences how long the male will continue his alarm calling. We tested three hypotheses that might explain the alarm calling duration of male Thomas langurs: the fatigue, group size and group member behaviour hypotheses. Fatigue and group size did not influence male alarm calling duration. We found that males only ceased calling shortly after all individuals in his group had given at least one alarm call. This shows that males keep track of and thus remember which group members have called. [ABSTRACT FROM AUTHOR]

Female social dispersal in primates differs from the general mammalian pattern of locational dispersal. Both nulliparous and parous females may disperse to another group. Several hypotheses can explain female social dispersal: reduction of predation risk, inbreeding avoidance, and offspring protection through mate choice. We tested these hypotheses with an extended data set of Thomas langurs (Presbytis thomasi) and investigated parameters of male behaviour that females may use in their dispersal decisions. Data were collected over a 12.5-year period from a wild population in Sumatra, Indonesia, allowing for some critical tests of the hypotheses. Females dispersed to a group smaller than their original one, thereby refuting the predation risk hypothesis. Maturing nulliparous females only dispersed when their father was resident. Therefore, dispersal by nulliparous females was best explained through inbreeding avoidance. Parous females transferred to young, adult males. These males provided better protection to offspring against predation and infanticide than the old, late tenure males. Therefore, females transfer to better protector males. The male behavioural cues that females use to assess male quality were unclear. Females, however, may use proxies of male age, such as group composition and acoustical characteristics of loud calls, as indicators of male quality. The results suggest that female mate choice is an important function of social dispersal by parous females. Its importance in locational dispersal remains to be investigated. [ABSTRACT FROM AUTHOR]

Socioecological theory suggests a link between the strength of competition for food/safety, rates of agonism, structure of dominance hierarchies, and dispersal among group-living females. This study presents preliminary data on agonistic behavior and dominance relationships for female Phayre's leaf monkeys (Trachypithecus phayrei), a species in which females routinely disperse. Behavioral observations were conducted on two groups (four adult females, and five adult females plus two juvenile females, respectively) at Phu Khieo Wildlife Sanctuary, northeast Thailand. Rates of agonistic behavior were analyzed from focal continuous recordings, while dominance hierarchies were constructed from all agonistic behaviors (focal and ad libitum sampling). Overall, female-female agonistic behaviors (aggression, submission, and displacements) occurred at a rate of <0.25 interactions per hour. Agonistic interactions involving food occurred more frequently than expected based on feeding time. Females in both groups exhibited linear dominance hierarchies with some reversals, and possibly an age-inversed hierarchical structure in the larger group. The results fit well with previous results for colobine monkeys regarding frequency of interactions, displacements predominating agonistic behavior, and the possibility of an age-inversed hierarchy. The results contradict the suggested link between linearity of hierarchies and female philopatry. Future studies should consider the notion that female dispersal may coexist with linear dominance hierarchies. [ABSTRACT FROM AUTHOR]