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A variety of social systems have evolved as a consequence of competition and cooperation among individuals. Giraffe ( Giraffa camelopardalis sp.) societies are an anomaly because the dearth of long-term data has produced two polar perspectives: a loose amalgamation of non-bonded individuals that sometimes coalesce into a herd and a structured social system with a fission-fusion process modifying herd composition within a community. We analysed 34 years of data collected from a population of Thornicroft's giraffe ( G. c. thornicrofti, Lydekker 1911) residing in South Luangwa, Zambia, to establish the nature of giraffe society. Our sample consisted of 52 individually recognized animals. We found that giraffe herd composition is based upon long-term social associations that often reflect kinship, with close relatives significantly more likely than non-relatives to establish herds. Mother/offspring dyads had the strongest associations, which persisted for years. Giraffe live in a complex society characterized by marked flexibility in herd size, with about 25% of the variance in herd composition owing to kinship and sex. We suggest that giraffe herds share many characteristics of fission-fusion social systems and propose that sophisticated communication systems are a crucial component regulating subgroup dynamics. [ABSTRACT FROM AUTHOR]

The article offers the author's insights on the reaction of a giraffe cow to its newborn calf's death. The author relates his observations of giraffes which lead to a firm basis for efforts to study social bond development. He discusses various cases of giraffe's reaction that imitate those of African elephants and chimpanzees. He adds that the animal's maternal reaction to the dead offspring was not as sustained as African elephants' reactions.

Two central concerns for elephant husbandry and management are whether zoological enclosures are appropriately sized and the degree to which naturalistic exercise and activity are observed in such enclosures. In order to address these issues, accurate data on the daily walking distance of elephants both in situ and ex situ are necessary. We used an accelerometer, a pedometer that measures step count and activity level, to estimate walking distance in African elephants ( Loxodonta africana) at the San Diego Zoo's Wild Animal Park. The accelerometer was worn simultaneously with a GPS unit that recorded actual walking distance. Estimates of walking distance were extrapolated from the accelerometer and compared with actual distances determined by GPS data. The accelerometer was found to overestimate step count, and subsequently walking distance, by including false counts of steps. Extrapolating walking distance based upon stride length measurements did not match actual GPS walking distance. However, activity level output from the accelerometer significantly correlated with actual GPS walking distance. In addition, we report that the rate of movement is comparable to that reported in other zoological settings. We provide a linear regression equation that can be utilized by other institutions to estimate daily walking distance of elephants in their collection who are outfitted with accelerometers. Zoo Biol 30:579-591, 2011. © 2010 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

A comprehensive review of women's dietary behavior across the menstrual cycle suggests a drop in caloric intake around the time of ovulation; similar patterns occur in many other mammals. The periovulatory nadir is puzzling, as it is not explicable in terms of changes in the energy budget. Existing explanations in the animal literature opiate wholly at the proximate level of analysis and hence do not address this puzzle. In this paper, I offer an ultimate explanation for the periovulatory feeding nadir; arguing that the decrease in the set point for satiation during the fertile period of the female cycle is an adaptation produced by natural selection in order to reduce the motivational salience of goals that compete with those directly or indirectly pertaining to mating. In support of this explanation, I adduce evidence of: a) periovulatory reductions in other ingestive behaviors, and b) periovulatory increases in motor activity and the psychological concomitants thereof. [ABSTRACT FROM AUTHOR]

Gene conversion and balancing selection have been invoked to explain the ubiquitous diversity of the antigen-presenting proteins encoded in the vertebrate major histocompatibility complex (MHC). In the present study, direct evidence for over-dominant selection promoting MHC diversity in primates is provided by the observation that, in a large free-ranging population of rhesus macaques, males heterozygous at MHC class II locus Mamu-DQB1 sired significantly more offspring than homozygotes (the male-specific selection coefficient s equals 0.34). This heterozygote advantage appeared to be independent of the actual male Mamu-DQB1 genotype. No similar effect emerged for a captive group of monkeys of similar genetic background but under veterinary care. [ABSTRACT FROM AUTHOR]

Body size is associated with menarche and ovarian function, but the relationship to first conception is rarely examined. We conducted a longitudinal investigation of rhesus macaques, Macaca mulatta , to determine the effect of differences in body weight on both the age at first conception and survivorship of first progeny. Young females who became pregnant weighed significantly more than peers who remained barren, with weight changes for females who successfully raised offspring no different than those for females who did not produce offspring. Infant mortality among primiparae was not significantly greater than that among multiparae, although nearly twice as high. First-born males tended to have lower survivorship than first-born female offspring. We suggest that reproductive costs encountered by primiparous females are more likely to be modulated by immature neuroendocrine function than by inexperience, small body size, or infant suckling patterns. We conclude that body size influences probability of first conception, socioendocrine factors mediate the likelihood of infant survival, and primiparous production of male progeny seems to exert a greater reproductive cost than does production of female progeny. Am. J. Primatol. 46:135–144, 1998. © 1998 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

The goal of this study was to develop a relatively noninvasive technique for generating ovulatory estrogen levels in cycling females over extended periods of time. Eleven intact cycling rhesus macaques were given weekly injections of estradiol cypionate in an effort to obtain weekly levels which approximated ovulatory levels. A dose of 500 μg generated weekly estrogen values averaging 370 ± 18 pg/ml. This method is a satisfactory alternative to more traditional techniques. It involves no surgical procedures, it is relatively nonintrusive, it does not terminate a female's reproductive career, and it is not as time-consuming as daily injections. Female cycle state can be altered with a minimum of manipulation for studies involving the behavior of estrous females. [ABSTRACT FROM AUTHOR]

The study reported here tested Altmann's prediction [Baboon Mothers and Infants. Cambridge, Harvard University Press, 1980] that lactating female baboons endure a weight loss. Data from 64 adult female olive baboons (Papio anubis) residing in six troops in Kenya revealed that reproductive condition was related to weight. Lactating females weighed less and pregnant females weighed more than cycling females. There was a negative correlation between the weight of cycling females and the number of months postweighing to their next conception. These results indicate that lactation in wild baboons imposes energy costs that result in lost weight. It is suggested that female baboons may have th surpass a minimum weight threshold prior to resumption of postlactational cycling and that nutritional status is more influential than rank in affecting female reproductive success. [ABSTRACT FROM AUTHOR]

Rape has been posited to be an outgrowth of male reproductive strategies. Forced copulations may have evolved as a consequence of the low parental investment made by males in producing and raising offspring. We designed a laboratory experiment which paired rhesus macaque males with females in order to assess the influence of intersexual aggression on male sexual activity. Younger and older adult males had comparable levels of sexual behavior, but younger males were more aggressive towards females than were older males. In addition, females threatened younger males more than older males. Male attacks on females did not result in sexual intercourse. On the contrary, a negative correlation existed between male aggression towards females and male success at achieving intromissions. Female aggression towards males appeared to be an effective tactic which reduced the chances of sexual intercourse. We conclude that intersexual aggression acts either as a mechanism of dominance assertion or as a means to increase spatial distance between individuals. These data do not support the idea that rape in humans has an evolutionary foundation derived from male reproductive strategies. [ABSTRACT FROM AUTHOR]

Asserts that paternal relatedness and age proximity regulate social relationships among adult female rhesus macaques. Effect of both maternal and paternal kinship, as well as age proximity, on affiliative interactions among semifree-ranging adult female rhesus macaques, Macaca mulatta; Observation pertaining to parental kin discrimination.

Salivary alpha-amylase (sAA) enzyme functions as a digestive enzyme in many species that consume starch in their diet. Human studies have also revealed that sAA enzyme activity levels are positively correlated with the release of the stress hormone norepinephrine, allowing sAA to act as a biomarker for sympathetic nervous system activity. Recent non-human primate studies have incorporated sAA as a physiological stress marker. However, no published reports have investigated the time course of sAA from a stressful event to return to baseline levels in non-human primates. Furthermore, no validation of sAA as a stress biomarker has been reported for Japanese macaques (Macaca fuscata). This study had two primary aims: (1) to develop a systematic method for non-invasive saliva collection and, (2) to investigate sAA as a biomarker of acute stress in M. fuscata in order to better understand its acute stress-related characteristics. We developed a non-invasive method for cooperative saliva collection using positive reinforcement training (PRT) and tracked individual progress over 595 trials in ten individually housed Japanese macaques. We detected sAA enzyme in M. fuscata via kinetic reaction assay, then performed 22 acute stress tests. Four tests met conditions for interpreting sAA in response to an acute stressor and these results show that on average sAA activity rapidly increased post-stressor (mean ± SD = 4.2 ± 0.9 min) and returned to baseline shortly thereafter (10.4 ± 0.6 min). Our report reveals for the first time the temporal dynamics of sAA when applying acute stress to Japanese macaques and could be a useful tool for assessing animal welfare.

The ability of animals to survive dramatic climates depends on their physiology, morphology and behaviour, but is often influenced by the configuration of their habitat. Along with autonomic responses, thermoregulatory behaviours, including postural adjustments, social aggregation, and use of trees for shelter, help individuals maintain homeostasis across climate variations. Japanese macaques (Macaca fuscata) are the world's most northerly species of nonhuman primates and have adapted to extremely cold environments. Given that thermoregulatory stress can increase glucocorticoid concentrations in primates, we hypothesized that by using an available hot spring, Japanese macaques could gain protection against weather-induced cold stress during winter. We studied 12 adult female Japanese macaques living in Jigokudani Monkey Park, Japan, during the spring birth season (April to June) and winter mating season (October to December). We collected faecal samples for determination of faecal glucocorticoid (fGC) metabolite concentrations by enzyme immunoassay, as well as behavioural data to determine time spent in the hot springs, dominance rank, aggression rates, and affiliative behaviours. We used nonparametric statistics to examine seasonal changes in hot spring bathing, and the relationship between rank and air temperature on hot spring bathing. We used general linear mixed-effect models to examine factors impacting hormone concentrations. We found that Japanese macaques use hot spring bathing for thermoregulation during the winter. In the studied troop, the single hot spring is a restricted resource favoured by dominant females. High social rank had both costs and benefits: dominant females sustained high fGC levels, which were associated with high aggression rates in winter, but benefited by priority of access to the hot spring, which was associated with low fGC concentrations and therefore might help reduce energy expenditure and subsequent body heat loss. This unique habit of hot spring bathing by Japanese macaques illustrates how behavioural flexibility can help counter cold climate stress, with likely implications for reproduction and survival.

Population control is essential for animal welfare and human safety in free-ranging or captive settings, especially when resources are limited. As an alternative to lethal control, contraceptive methods such as castration in males can be a practical solution, because the testicles are a visual cue to determine which males have been sterilized. However, careful analyses should be carried out to ensure no disruption in the social structure of the population. Japanese macaques (Macaca fuscata) live in a society centered around dominance rank and matrilineal kin relationships. Testosterone and glucocorticoids have been correlated with dominance rank in humans and other species, but previous studies in Japanese macaques were inconclusive. This study aimed to investigate behavioral and physiological differences between castrated and intact male Japanese macaques, and to examine the effect of season and behavior in hormonal concentrations in intact males. Our subjects were six intact males from Jigokudani Monkey Park (Japan) and 13 castrated males from Born Free Primate Sanctuary (USA). We collected behavioral data using both focal and ad libitum sampling, and fecal samples for determination of testosterone (fT) and glucocorticoids (fGC) by enzyme immunoassay. We found that castrated males exhibited a social hierarchy, but not a linear hierarchy, as was the case in intact males. Castrated males were less aggressive than intact males, probably because fT concentrations were lower in the castrated males. Age was positively correlated with fGC levels, while fT concentrations were lower in old males than younger adult males. Fecal T levels correlated with both rank and atmospheric temperature. In intact males, both fGC and fT levels were elevated during the mating season. We found a negative correlation between fGC levels and the amount of grooming received. Our findings indicate that castration had a minimal impact on sociality, with season, temperature, and rank all influencing male sex steroid levels in intact males. Our study indicates that castration can be adopted as a population control mechanism without drastically altering the social relationships of males., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Genetic studies not only contribute substantially to our current understanding of the natural variation in behavior and health in many species, they also provide the basis of numerous in vivo models of human traits. Despite the many challenges posed by the high level of biological and social complexity, a long lifespan and difficult access in the field, genetic studies of primates are particularly rewarding because of the close evolutionary relatedness of these species to humans. The free-ranging rhesus macaque (Macaca mulatta) population on Cayo Santiago (CS), Puerto Rico, provides a unique resource in this respect because several of the abovementioned caveats are of either minor importance there, or lacking altogether, thereby allowing long-term genetic research in a primate population under constant surveillance since 1956. This review summarizes more than 40 years of genetic research carried out on CS, from early blood group typing and the genetic characterization of skeletal material via population-wide paternity testing with DNA fingerprints and short tandem repeats (STRs) to the analysis of the highly polymorphic DQB1 locus within the major histocompatibility complex (MHC). The results of the paternity studies also facilitated subsequent studies of male dominance and other factors influencing male reproductive success, of male reproductive skew, paternal kin bias, and mechanisms of paternal kin recognition. More recently, the CS macaques have been the subjects of functional genetic and gene expression analyses and have played an important role in behavioral and quantitative genetic studies. In addition, the CS colony has been used as a natural model for human adult-onset macular degeneration, glaucoma, and circadian rhythm disorder. Our review finishes off with a discussion of potential future directions of research on CS, including the transition from STRs to single nucleotide polymorphism (SNP) typing and whole genome sequencing., (© 2016 Wiley Periodicals, Inc.)

As part of a health investigation on koalas at San Diego Zoo, serum samples were analyzed from 18 free-ranging and 22 zoo-based koalas, Phascolarctos cinereus. Serum concentrations of calcium, chloride, cobalt, copper, iron, magnesium, manganese, molybdenum, phosphorus, potassium, selenium, sodium, zinc, and vitamins A, E, and 25(OH)D3 were quantified. Calcium, chloride, molybdenum, selenium, and vitamin E concentrations were significantly higher in zoo-based koalas than in free-ranging koalas, whereas magnesium, manganese, phosphorus, and zinc concentrations were significantly higher in the free-ranging koalas. No significant differences were found between genders. The results from this study will help to establish a starting point for determining target circulating nutrient concentrations in koalas.

Dehydroepiandrosterone (DHEA) and its sulfate, DHEAS, are the most abundant steroid hormones in primates, providing a large reservoir of precursors for the production of androgens. DHEAS levels decline with age in adult humans and nonhuman primates, prompting its consideration as a biomarker of senescence. However, the mechanisms responsible for this age-related decrease and its relationship to reproduction remain elusive. This research investigated DHEAS concentrations in fecal samples in order to determine age-related changes in captive Japanese macaques, as well as to assess the possible influence of seasonality. The subjects were 25 female Japanese macaques (2weeks to 14years-old) housed outdoors in social groups at the Primate Research Institute. We collected three fecal samples from each animal during the breeding season (October to December) and three additional samples from adult females during the non-breeding season (May to June). The hormonal concentrations were determined using enzyme immunoassay. DHEAS concentration was negatively correlated with age, but we did not find a significant difference between breeding and non-breeding seasons. Neonatal macaques had the highest DHEAS concentrations of all age groups. We suggest that elevated neonatal DHEAS is possibly a residue from fetal adrenal secretion and that, as in humans, it might assist in neurobiological development., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Giraffe herds have been characterized as random associations of individuals, but recent evidence suggests giraffe have a more complex social structure. The authors formulated 3 hypotheses designed to evaluate whether a herd of captive giraffe (Giraffa camelopardalis) associated randomly or patterned their behavior and proximity in a manner indicative of social relationships. Affiliative interaction, proximity, and nearest neighbors for 6 captive female giraffe living in a large outdoor enclosure were analyzed, and all three measures were nonrandomly distributed, indicating female giraffe had social preferences. Furthermore, preferences were consistent across measures and time, suggesting that adult female giraffe maintain relationships. Mother-daughter pairs and pairs with large age differences between members interacted and associated most often. The social structure of this captive herd is influenced by social relationships between individual adult females, and the social behavior of individual females should be examined more closely in the wild.

Prior to 1985 tetanus was a major cause of mortality in the free-ranging colony of rhesus monkeys on Cayo Santiago, accounting for almost a quarter of annual deaths. In 1985 and 1986 all animals (except infants) received primary and booster doses, respectively, of tetanus toxoid. In subsequent years primary immunizations were given to all yearlings, and boosters were administered to all 2-year-old animals during the annual capture of the colony. The main objectives of the tetanus immunization program were to reduce the pain and suffering caused by tetanus infections and to decrease mortality in the colony. Other objectives were to evaluate the efficacy of the two-dose tetanus toxoid immunization protocol and to determine whether additional boosters might be required to provide adequate long-term protection against tetanus infections. The immediate effect of the mass immunization program was the elimination of clinical tetanus infections in the population and a 42.2% reduction in the overall mortality rate. Since the immunization program began, no cases of tetanus have been observed in the colony, except in two unimmunized infants, and it has not been necessary to give tertiary injections of tetanus toxoid to maintain protection against infection. A sample collected in 2004 of the original cohort of monkeys immunized in 1985 and 1986 showed that 93.3% (14/15) had protective tetanus antibody titers (>0.01 IU/ml) at the ages of 20-23 years, which is close to the life expectancy of the Cayo Santiago rhesus macaques. Two intramuscular doses of tetanus toxoid provided long-term, if not lifelong, protection against tetanus for rhesus monkeys living in a tropical clime where tetanus is enzootic and the risk of infection is great., ((c) 2005 Wiley-Liss, Inc.)

One of the basic tenets of sexual selection is that male reproductive success should be large in polygynous species. Here, we analysed 6 years of molecular genetic data from a semi-free-ranging population of rhesus macaques (Macaca mulatta), using Nonac's B index, to assess the level of male reproductive skew in the study troop. On average, the top sire in each year produced 24% of the infants, while 71% of troop males sired no offspring at all. Consequently, 74% of infants had at least one paternal half-sibling in their own birth cohort. Reproductive success was greatest for high-ranking males, males who spent the whole mating season in the troop and males of 9-11 years of age. Heterozygosity for major histocompatibility complex (MHC) class II gene DQB1 was the strongest single predictor of male reproductive success. A negative relationship suggestive of female mate choice was noted between the B index and the proportion of extragroup paternities. Reproductive skew was not associated with relatedness among potential sires or with female cycle synchrony. We conclude that reproductive skew in male rhesus macaques is best accounted for by the 'limited-control' model, with multiple factors interacting to regulate individual reproductive output.

In many mammalian species, male reproductive success appears to climb sharply at young adulthood, form a brief plateau during prime ages, and decline among older animals, a pattern often attributed to reduced physical condition with ageing. However, solid evidence to either substantiate or refute this profile among nonhuman primates is lacking. Here, we combine a decade of genetic analysis of paternity among free-ranging rhesus macaques, Macaca mulatta, with information about body condition in order to evaluate how changes in morphology might govern age-specific reproduction among males. We show that age-specific reproductive success traverses the same life history profile as found in other mammals, but reductions in reproductive output with advanced age were associated with reduced chances of survivorship rather than accompanied by diminished body condition. We demonstrate that variance in male age at onset of reproduction is three times greater than variance in female age at onset of reproduction. We provide the first evidence from primates that age-specific reproductive output among males is not a consequence of age-related changes in body condition, but reflects social and demographic factors.

The circulating level of homocysteine (Hcy) is recognized as a major independent risk factor for cardiovascular disease in humans. Nonhuman primates are being investigated to see whether they will be accurate models for Hcy indicators of cardiovascular dysfunction. Normal reference values are available in humans for Hcy as classified by age, gender, ethnic origin, and biological factors, however similar information in nonhuman primates had not been published previously. The purpose of this report is to provide normal Hcy values in a large group of nonhuman primates in light of age, gender, and physiologic state (pregnancy and lactation) and to compare these values to the same parameters in humans to highlight similar and dissimilar trends. In addition, plasma levels of folic acid and vitamin B(12), which are determinants of Hcy status in humans, are presented. Samples obtained from a troop of 149 rhesus monkeys (Macaca mulatta) fed a high protein commercial diet were analyzed for Hcy by using high-performance liquid chromatography. Folate and vitamin B(12) levels were determined by using an autoanalyzer. Results (mean [95% confidence interval]) for the entire troop were: Hcy, 4.5 (4.2-4.9) micromol/L; folic acid, 8.6 (8.0-9.1) micromol/L; and vitamin B(12), 673 (611-741) pmol/L. Quantitative values are similar to published values for another species of wild-caught macaques. Similar to trends noted for humans, male monkeys had higher Hcy values than did female animals, pregnant animals had lower values than did nonpregnant ones, and Hcy levels were inversely proportional to plasma folate and vitamin B(12) concentrations. However, homocysteine levels in rhesus monkeys did not vary consistently with age, whereas they increase with age in humans.

One component of sexual selection is sperm competition. It has been reasoned that the intensity of sperm competition may be reflected in the relative testicular sizes of animals. Among males residing in multimale breeding systems, testicular size is relatively larger than among males residing in unimale mating systems. Information on whether differences in testicular size within a species can account for differences in male reproductive success is unavailable for natural populations of primates. A population of six troops of savanna baboons in Kenya was surveyed for morphometric analysis, and one of these troops was the subject of extensive behavioral observations afterwards. Testicular weights could not be obtained, but measurements of linear dimensions were transformed into volumetric estimates. Male weight accounted for 30% of the variance in testicular volume. Neither body size nor testicular volume was associated with differences in male reproductive activity. The outcome of fights over access to females could not be related to male body size, and ejaculatory patterns of males were independent of testicle size. Both sperm competition and aggressive competition intensified during the four-day optimum conception period, but fights over access to consort females were infrequent. Among savanna baboons, the probability of an ejaculation resulting in a conception is fairly low, which may account for the infrequency of injurious fights. Although testicle size influences sperm production, it does not influence either the timing of mating or the fertilizing capacity of spermatozoa, and both of these factors probably account for a substantial fraction of the variance in male baboon paternity. Sperm competition is an adjunct to agonistic competition as a mechanism affecting male baboon reproductive success. It is concluded that male reproductive success in baboons is affected more by social factors than by morphological traits associated with size., (© 1989 The Society for the Study of Evolution.)