Showing papers in "American Journal of Primatology in 1983"

Diet and dominance among female vervet monkeys (Cercopithecus aethiops).

Abstract: Behavioral observations of free-ranging female vervet monkeys (Cercopithecus aethiops) suggest that priority of access to food enhances individual fitness. Seventeen adult females living in two social groups were observed for 26 months in the Samburu/Isiolo Game Reserves, northern Kenya. Priority of access to feeding and sitting sites was associated with significant differences in diet and reproduction. Food species distribution altered rank-related differences in diet. Rank-related differences in diet occurred when food items were clumped in distribution, but not when they were randomly distributed. The relation of individual food items to reproduction influenced rank-related differences in reproduction. Rank was significantly correlated with birth rate when a preferred food species was clumped in distribution.

Two new species of night monkeys, genus Aotus (Cebidae, platyrrhini): A preliminary report on Aotus taxonomy.

Abstract: The nine allopatric species of Aotus recognized represent two natural groups distinguished by karyotype, color, and pelage patterns. Correlated with these group characters are reported differences in serum proteins and degrees of susceptibility or immunity to experimental infection with malarial parasites. The primitive gray-neck species group of Aotus contains A. brumbacki (new species), A. lemurinus (with subspecies lemurinus and griseimembra), A. trivirgatus, and A. vociferans. The derived red-neck group contains A. nancymai (new species), A. miconax. A. infulatus, and A. azarae (with subspecies azarae and boliviensis). Only the two new species are described but a key to the species and subspecies gives the diagnostic characters of each. The gray-neck group occurs almost entirely north of the Amazon, the red-neck group almost entirely south. The distributional exceptions are enclave populations resulting from river bend cutoffs. Formation of an enclave population of A. nancymai is discussed and available information on the biology of this species is reported.

Endocrine aspects of social instability in the olive baboon (Papio anubis).

Abstract: The relationships among social status and the cortisol and testosterone stress-response were studied in the non-natal male members of a troop of olive baboons (Papio anubis) before and during a period of social instability. The unstable period was characterized by dominance interactions that were more frequent, more inconsistent, and produced less linear hierarchies than during the stable period. These changes occurred predominantly among the high-ranking males. Such males engaged in coalitions and consortship harassments at a higher rate during the unstable period than during the stable period. Finally, high-ranking males had the highest rates of involvement in and initiation of escalated fighting during the unstable period, in contrast with the stable period. A number of endocrine correlates of instability emerged. During the stable period, high-ranking males (by reproductive criteria) showed an endocrine profile different from that of subordinates. They had the lowest basal cortisol titers, the largest and fastest increases in cortisol titer during stress, and had elevated testosterone titers during stress. None of these attributes was found in high-ranking males during the unstable period. Males during the unstable period had elevated basal cortisol titers, suppressed cortisol responsiveness to stress, and no longer showed elevated testosterone titers during stress. When psychological advantages associated with social status in a stable social environment were lost, endocrine efficiency previously associated with social status was apparently also lost. Further, high-ranking males, who were most aggressive exclusively during the unstable period, had the highest absolute titers of testosterone exclusively during the unstable period. Thus, elevated testosterone and high levels of aggression were unrelated to social status during the period of social stability, but were traits associated with dominant individuals during the unstable period.

Growth curves, dental emergence norms, and supplementary morphological observations in known‐age captive orangutans

Abstract: Postnatal development in known-age captive orangutans was studied by collating new data from seven orangutans at Chicago Zoological Park, Brookfield, Illinois, with published and unpublished data from 76 additional captive orangutans. Norms were tabulated for deciduous and permanent dental emergence. Growth curves for weight and linear dimensions in females and males were compared in captive-reared and wild-reared subjects. Hand-reared and mother-nursed captives were compared with respect to dental emergence and weight increase. Differential relative growth of extremity segments was investigated. Pedigree data are presented relative to genetics of hallucal nail absence. Males of various ages were compared with respect to testis size and location and cheek-pad development.

Brief report: Infant-killing and infant disappearance following male takeovers in a group of free-ranging howling monkeys (Alouatta palliata) in Costa Rica.

Abstract: Events surrounding an infant-killing following a male takeover are described for a group of free-ranging howling monkeys in Costa Rica, and additional evidence is presented for infant disappearances following three previous male takeovers. Infant-killing is best interpreted in this context as a male reproductive strategy, as infant-killing did effectively shorten the interbirth interval, and only infants of high-ranking females died or disappeared following a male takeover. Due to the exclusive access of the dominant male to high-ranking estrous females, an incoming male who had lived as a peripheral male before taking over the group would run little risk of eliminating his own offspring in the course of killing the offspring of high-ranking females.

Sexual dimorphisms in the overall proportions of primates.

Abstract: Morphometric analysis of Professor A.H. Schultz's data on the overall proportions of primates reveals differences between the sexes. Univariate examinations of these data confirm the existence of the spectrum of sexual dimorphism already well known. This spectrum relates mainly to differences in the proportions of the trunk. It has a differential expression with largest differences between the sexes in species such as orangutans and boboons, and smallest in species such as spider monkeys and douroucoulis. Multivariate statistical study of these same data reveal, however, further unsuspected sexual dimorphisms. Although differences between the sexes are only small when measures of the relative lengths of bodily parts are examined, they are big when bodily breadths are studied. Investigation of breadths alone reveals that the primates display two major patterns of sexual dimorphisms and seven unique sexual dimorphisms among the 18 genera examined. Such findings mean that sexual dimorphism of bodily structure is not a single phenomenon with differential expression, a concept widely noted in the literature and most recently associated with social organization. There are several different sexual dimorphisms and this suggests that their causation is likely to be multifactorial with multiple complex interactions among the factors. Some of the sexual dimorphisms must have evolved in parallel a number of times, and, given that chimpanzees, gorillas, and humans each display a different sexual dimorphism, at least some of the evolutionary changes in different sexual dimorphisms must be very recent. The findings even imply the possibility of further unique patterns of sexual dimorphism in some fossils. By further extension, the findings may have some implications for our understanding of nonstructural dimorphisms in humans.

Personality traits of adolescent pig-tailed monkeys (Macaca nemestrina): An analysis of social rank and early separation experience.

Abstract: Personality ratings of ten adolescent pig-tailed macaques (Macaca nemestrina) were carried out by three experienced observers who used a simple three-point rating system. A modification of Stevenson-Hinde & Zunz's [1978] procedure, the agreement between raters on each of 21 traits was evaluated. When correlated with social rank, it was shown that dominant animals were rated as being, for example, confident, effective, and opportunistic. Subordinant monkeys were rated as insecure and dependent. Rank correlated negatively, however, with observers' impressions of popularity. Subjects who had undergone a brief maternal separation were rated as less sociable than their nonseparated counterparts. Furthermore, rank-related traits corresponded well with the three personality components that were derived by Stevenson-Hind & Zunz [1978]; this suggested that clusters of traits reliably accompanied and/or contributed to the attainment of social rank.

The effects of dominance on mating behavior and paternity in a captive troop of rhesus monkeys (Macaca mulatta)

Abstract: The effects of social dominance on male mating behavior and paternity in a troop of rhesus monkeys (macaca mulatta) were examined. A wild-caught troop of monkeys, captured in India in 1972, has been monitored in captivity for eight years. Some animals have been culled from this troop, but no new animals have been added except through births. The social structure of the troop has remained fairly stable over the eight years, although the number of adult males at any given time has ranged from four to ten. We blood typed 77 offspring born between 1973 and 1980 that survived to two months of age and determined paternity for 48 of them. During the eight-year period, the dominant male sired only 13% to 32% of the offspring, even though he participated in 67% of the observed copulations. In contrast, the second ranking male sired 30% to 48% of the offspring, but participated in only 14% of the observed matings. The frequency and duration of copulation in any one year appeared to reflect a male's rank in the dominance hierarchy. However, in all but one year of our study, the largest number of offspring were sired, not by the dominant male, but by young males who were second or third in rank. Nevertheless, the dominant male may have a selective advantage because he sires a large number of offspring early in life, and continues to produce offspring over many years. This study demonstrates that observed copulations are imprecise indicators of paternity, and that paternity in any one breeding season is a poor indicator of the genetic structure of a population.

Abortion following the immigration of an adult male baboon (Papio cynocephalus)

Abstract: Three abortions and the death of a vigorous infant occurred in a baboon (Papio cynocephalus) group in Amboseli National Park, Kenya, within the two weeks following the immigration of an aggressive adult male. The immigrant male attained top-ranking dominance status in the group prior to these events. Circumstantial observations suggest that the reproductive losses were related to persistent intense aggression from the immigrant adult male. In the past ten years, only three other miscarriages have occurred in Amboseli. Inducement of abortion is discussed as a reproductive tactic that may be available to males of mammalian species whose life histories favor the evolution of infant-killing by males.

Brief report: Chimpanzees, tools, and termites: New record from Gabon.

Abstract: Wild chimpanzees (Pan troglodytes) in northeastern Gabon use tools made of vegetation to obtain termites (Macrotermes? nobilis) for food. They mostly use probes in termite fishing, as recorded elsewhere in eastern and far western Africa. This is the first record of termite fishing by the central west African race of chimpanzees. There are signs that they also use stouter tools, perhaps to perforate the mounds of the termites. These new findings further complicate the status of material culture in this species of ape in nature.

Mirror-image responses in pygmy marmosets (Cebuella pygmaea).

Abstract: Only a few nonhuman species (chimpanzees and orangutans) have displayed mirror-image recognition of themselves by grooming at a spot that can only be seen with the mirror. Pygmy marmosets have never been observed to self-groom, but they do behave toward mirrors in a manner suggestive of the early stages of mirror-image recognition. They displayed a rapid extinction of social threat responses to their own image and of novelty responses to mirrors, but continued to show mirror-specific responses such as following their own image, playing peek-a-boo, and looking at their image throughout a 28-day period of mirror exposure. The pygmy marmosets used a mirror to locate otherwise unseen conspecifics from other groups and directed threat responses toward the real location of these animals rather than to their mirror-image. Pygmy marmosets displayed the precursor behaviors to mirror-image recognition.

Physiological and social influences on mounting behavior of troop-living female monkeys (Macaca fuscata)

Abstract: Female mounting behavior was studied in a troop of Japanese macaques during one breeding season. Of 79 sexually active females, mounting behavior during consortships was shown by 50 females; 13 only with males, 20 with both males and females, and 17 only with females. Several factors associated with reproductive state influenced the expression of mounting activity. Recency of parturition influenced the mounting by females regardless of the type of partner. Females that had not given birth the previous spring (four to six months prior to the period of observation) were more likely both to mount partners and to produce an infant the following spring. These findings suggest the existence of a common factor, perhaps associated with lactation, inhibitory both to expression of mounting and to female fertility. Additionally, females that mounted were more likely to do so in consortships that followed than in those that preceded conception. This last finding suggests that, in this social context, the endocrine conditions of early pregnancy facilitated mounting to a greater extent than those associated with the cyclic ovary. Separate statistical analyses examined possible influences of age, dominance rank, and kinship on the likelihoods of mounting and being mounted. None of these factors influenced female mounting. Results suggest that the expression of mounting by females was more influenced by reproductive state than by social characteristics of the partner.

Taxonomic note: Bunopithecus: A genus-level taxon for the hoolock gibbon (Hylobates hoolock).

Abstract: The recent discovery that the hoolock gibbon (Hylobates hoolock [Harlan, 1834]) has a karyotype distinct from all other hylobatids provides a new and strong motive for revising gibbon taxonomy and establishing hoolocks in a separate, higher taxon. Revising Groves's taxonomy of 1972, we propose that hoolock, along with the fossil species sericus, occupy a subgenus, Bunopithecus. With the newly added taxon, the genus Hylobates would thus contain four subgenera: Bunopithecus, Hylobates, Nomascus, and Symphalangus.

Brief report: Outbreak of severe aggression in captive Macaca mulatta

Abstract: An outbreak of severe aggression occurred among females in a rhesus macaque breeding group at the California Primate Research Center four years after the group was established. During the breeding season in which this occurred, the incidence of injured females in other breeding groups at the Primate Center was significantly higher than in the previous year. This breeding season was the first in which a large number of females reached sexual maturity. The group in which the most severe aggression occurred contained the largest number and proportion of maturing females. Evidence suggests that the simultaneous maturation of a large cohort of adolescent females may be associated with increased levels of aggression, and that this aggression may be intensified by certain aspects of captivity.

Use of females by male olive baboons (Papio anubis).

Abstract: Wild male olive baboons (Papio anubis) used females and infants as agonistic buffers. Male residency status determined whether a male used females or whether they were used against him. The success of the strategy depended on the cooperation of the female and the context of the interaction. Female cooperation correlated with preexisting social affiliation with the male user. Male choice of female or infant buffers represented a compromise between the potential effectiveness of each in different situations and the social and spatial availability of females and infants. Nonreproductive social relationships may provide long-term strategic benefits to the individuals who invest in them.

Reproductive patterns in galagos (Galago zanzibaricus and Galago garnettii) in relation to climatic variability.

Abstract: The reproductive patterns (birth seasonality, litter size, litters per year) of two sympatric species of galago (Galago zanzibaricus and G. garnettii) were studied in a coastal forest in Kenya for a two-year period. Trap-retrap and radio tracking methods were employed. G. zanzibaricus has one infant twice per year; G. garnettii has one infant once per year. Both species are seasonal breeders. These East African galagos are intermediate in reproductive patterns when compared with galagos from South African woodland (G. senegalensis moholi and G. crassicaudatus umbrosis) and West African rainforest (G. alleni and G. demidovii). Climatic patterns (total annual rainfall, seasonal variability of rainfall, variability in total annual rainfall, and annual temperature variability) are also compared for the three regions. Climatically, East Africa is intermediate between West and South Africa in total annual rainfall and in seasonality of rainfall, but not in year-to-year variability in rainfall. East Africa shows the highest variability in annual rainfall. South Africa has the coldest dry seasons and highest variability in temperatures. The results of this study suggest that "r-selection" and "K-selection" do not provide adequate explanations of galago reproductive patterns.

The effect of peer separation in young chimpanzees (Pan troglodytes)

Abstract: Ten chimpanzees (Pan troglogytes), aged 18-24 months, housed without mothers as two dyads and two triads, were subjected to social separation. Two issues were addressed: the effects of peer separation in chimpanzees; and differential responses by subjects living in dyads compared with those living in triads. Chimpanzees that were alone during separation reacted with high levels of "protest" alternating with "despair" throughout the separation period. The continued presence of one cagemate, during separation from a third, was a strong mitigating factor. Even when the primary attachment was formed with the absent cagemate, the remaining chimpanzees clung to each other and the levels of protest and despair, when present, were low. Upon reunion, neither "detachment" nor heightened levels of clinging were conspicuous, but there was increased social interaction. The data on separation of chimpanzees are intermediate between those of humans and monkeys separated from mothers or peers. The increased social interactions during reunion, including looking, are comparable to the visual vigilance reported for humans.

A comparison of the behavior of Macaca fascicularis and Macaca mulatta in relation to the menstrual cycle.

Abstract: Observations on oppositely sexed pairs of M. fascicularis and M. mulatta revealed certain differences. M. fascicularis showed single-mount copulations, higher potency, less grooming activity, and milder but more frequent aggressive exchanges than the rhesus monkey. These differences might be due to the lower dominance gradient between the sexes and less sexual dimorphism in M. fascicularis than in M. mulatta. There were changes in the sexual, grooming, and aggressive interaction in relation to the menstrual cycle, indicating the suitability of M. fascicularis for hormone-behavior studies. Comparison of data from 30 and 60 min tests showed that important behavioral changes did not become apparent unless animals were given enough time to interact.

Ramapithecus and Sivapithecus from China: Some implications for higher primate evolution

Abstract: The pattern of overall dental dimensions in over 900 teeth of ramapithecines from Lufeng in China is examined using frequency distribution histograms and fitted normal curves, and compared with data for extant hominoids. A prior study has demonstrated unequivocally that at least two groups of animals must have existed at Lufeng [Wu and Oxnard, 1983; Oxnard, 1983a]. The present investigation confirms this finding in more detail. In addition it shows that one fossil group possesses smaller teeth with a lesser degree of sexual dimorphism and approximately equal numbers of adult males and females, and the other possesses larger teeth with a rather larger degree of sexual dimorphism and a female-male ratio that may have approximated from as low as 2:1 to as high as 4:1. Comparisons of patterns of difference along the tooth row demonstrate that both these forms differ from modern apes in their sexual dimorphism, the smaller form being more like humans than the larger, which is more like apes, especially orangutans. Comparisons of the areas of the canine teeth with each of the other functional segments of the tooth row again show that the smaller form is basically similar to modern humans and that the larger resembles extant great apes. Comparisons of other functional dental areas seem to relate to dietary and masticatory functions. Thus the cutting areas are large relative to the chewing areas in omnivorous humans, whereas in the essentially vegetarian great apes this ratio is smaller. The smaller fossil resembles the human condition and may have been somewhat omnivorous; the larger one more resembles the apes and may have been somewhat more vegetarian. However, these comparisons also show that the way in which the larger form resembles the apes is associated with special development of the canines, which is different from that in any modern ape. Comparisons show that the canines in the larger form project far beyond the normal line of tooth crowns. Finally, comparisons show that canine sexual dimorphism in height is marked in the larger form. Neither of these last two features is true of the smaller fossil. These findings have implications for our understanding of the evolution of early pongids and hominids, and for the evolution of primate sexual dimorphisms and dental mechanisms.

Karyotypic evolution in Aotus.

Abstract: Great karyotypic diversity exists within the platyrrhine genus Aotus. Primarily by comparing banded karyograms of different forms of Aotus, the pattern of karyotypic evolution can be assessed. Out-group comparisons are used to establish primitive and derived states of particular chromosomes, and a parsimonious cladogram is constructed. Other karyotypic changes are then positioned at appropriate nodes of the cladogram. The resulting phylogenetic hypothesis is entirely self-consistent, is in accord with out-group comparisons, does not invoke hybridization between ancestral forms, and, importantly, indicates a single origin for each rearrangement of euchromatic segments. Moreover, it is consistent with the hypothesis, derived from pelage studies, that the more southerly Aotus taxa constitute a holophyletic group. The reconstructed ancestral karyotype had a diploid number of 54. There has been little loss of euchromatic material during Aotus evolution.

Psycholinguistic analyses of alarm calls of Japanese monkeys (Macaca fuscata fuscata).

Abstract: Alarm and estrous calls emitted by Japanese macaques were recorded and analyzed in the Arashiyama West and East groups. Their responses to natural calls as well as to synthesized versions varying in the acoustic parameters that defined the vocalizations were studied. The response patterns shown by Arashiyama West group members, which were subject to a distinct change with only a slight difference of a single parameter, appeared to reflect strict underlying perceptual boundaries. This was analogous to the categorical perception that humans show with speech sounds. In contrast, continuous perception was exhibited by Arashiyama East group individuals. When several sounds were played back in combination to the former group, following stimuli were recognized by quite different cues from those by which the first sound was perceived. The groups' differences in vocal perception are discussed in terms of the ecological differences of the environments they inhabit.

Comparability of methods used in the sampling of primate behavior.

Abstract: Two measures of a behavior are defined as comparable if one is predictable from the other. The comparability of one-zero, instantaneous, actual-frequency, and actual-duration sampling was investigated using a Monte Carlo simulation to extend the range of sampling intervals beyond those ordinarily found in the literature. Several combinations of bout time, rate of response, and observation interval were simulated. Comparability between one-zero or instantaneous scores and actual frequency or actual duration was higher for higher behavior rates, decreased with longer observation intervals, and was usually higher for longer bout times. Curves of β2s from multiple regression analyses revealed a fundamental difference in the source of one-zero and instanteous predictability. Both actual frequency and actual duration contributed substantially to one-zero predictability, indicating high comparability between one-zero scores and a weighted combination of actual frequency and actual duration. Once the contribution of actual duration to instantaneous scores was accounted for, actual frequency contributed virtually nothing additional. Long-standing meanings of validity, reliability, and comparability were applied to the findings, resulting in the conclusion that all of the sampling methods are useful, depending upon the researcher's approach, resources, and problem.

The hemogram, serum biochemistry, and electrolyte profile of the free‐ranging Cayo Santiago rhesus macaques (Macaca mulatta)

Abstract: Sixty-four male and 33 female free-ranging rhesus monkeys (Macaca mulatta) from one of six social groups on the island of Cayo Santiago, Puerto Rico, were surveyed to establish normal values for the hemogram and serum biochemical and electrolytes for the colony. Mean values (± 1 SD) are reported by sex for each of three age groups (2–3, 4–9 and ≥ 10 years). All adult females (≥ 4 years) were pregnant. There were significant differences for a number of variables compared to the range reported in the existing literature, and among the age and sex groups in the sampled population.

Growth and development in the saddle‐back tamarin: The sequence and timing of dental eruption and epiphyseal union

Abstract: A cross-sectional sample of 121 colony-born saddle-back tamarins, Saguinus fuscicollis, was examined to identify the sequence and timing of dental eruption and epiphyseal union. The state of dental development of the deciduous and permanent dentitions was recorded as erupted or non-erupted on the basis of gingival penetration. Eighteen areas of union of long bone epiphyseal and other secondary centers, the union of the primary elements of the innominate, and the spheno-occipital synchondrosis were examined. The state of union at the areas was recorded on a three-point scale of not united, uniting, and united. The data indicated that deciduous incisors and canines were present at birth and that all deciduous teeth were erupted by 12 weeks. The first permanent tooth, M(1), erupted between weeks 16 and 23; the permanent dentition was fully erupted by 45 weeks. Union of the long bone epiphyses began in the third month at the distal humerus and continued until the first quarter of the second year. The secondary centers at the ischial tuberosity and iliac crest were united slightly later than four and six years of age, respectively. Regression analysis of the data indicate their potential use as parameters for predicting age in feral specimens.

Use of a radioreceptorassay (RRA) for human luteinizing hormone/chorionic gonadotropin (hLH/CG) for detection of early pregnancy and estimation of time of ovulation in macaques.

Abstract: A radioreceptorassay (RRA) for macaque luteinizing hormone (LH)/chorionic gonadotropin (CG) was adapted from the clinical RRA for human LH/CG, Biocept-G™, for the purposes of detection of pregnancy prior to day 20 of gestation and for estimation of the time of ovulation in macaques. The 90-min assay procedure was simple, accurate, and reliable. Seventy-five rhesus monkeys (Macaca mulatta) and 20 crab-eating monkeys (Macaca fascicularis) were tested for the presence of CG in the serum on estimated days 17-20 of pregnancy. Of a total of 160 tests, four false negative and 0 false positive tests were obtained, for an accuracy of 97.5%. The preovulatory LH peak was detected in 19 rhesus monkeys by semiquantitative RRA of LH/CG. Ovulation was confirmed in these 19 animals by the presence of a fresh corpus luteum at laparotomy 2-10 days after ovulation, collection of an embryo, pregnancy, or subsequent cycle history. The short, simple assay procedure and the low inter-and intraassay coefficients of variation (7.3 and 3.7%, respectively) allow use of this assay in an economical, predictive, as well as retrospective, capacity for estimation of the time of ovulation in rhesus monkeys. The sensitivity, reliability, species nonspecificity, simplicity, and rapidity of performance of this RRA for LH/CG are features which add up to a useful new management tool for breeding macaques for research purposes.

Parturition in Macaca nemestrina

Abstract: Measures were taken on 187 pregnancies of 104 pig-tailed macaques (Macaca nemestrina) to document the normative course of parturition and to identify factors correlated with high risk for poor pregnancy outcomes. Analyses involved weekly physical examinations and diurnal sleep-wake-fulness patterns during trimester three; behavior during labor and delivery; and newborn sex, Apgar ratings, birthweight, and reflexes. Onset of labor was estimated at three-four hours before delivery, the time when circadian activity level first deviated from its predelivery pattern. Active labor averaged 92 minutes, and was characterized by increased uterine contractions and manipulation of the vaginal area. The modal delivery time was 2200 hr through 2400 hr. Most infants emerged from the vulva in a cranial-anterior-anterior presentation, with only a brief pause between head expulsion and complete emergence. Females with histories of poor pregnancy outcomes were more likely to deliver after midnight and showed less labor-unique behavior than females with good outcome histories. Infants of high-risk females that were delivered after midnight had lower Apgar scores and more bruising than infants of low-risk females delevered before of after midnight, suggesting that high-risk females may have more difficult deliveries. Overall, the results show that simple direct observations of parturition can yield important quantitative normative information that is correlated with reproductive risk factors.

Red-bellied tamarins (Saguinus labiatus): Hematologic reference values and hemopathologic responses.

Abstract: Hematologic reference values have been established for captive adult red-bellied tamarins (Saguinus labiatus) by carrying out full blood counts and fibrinogen estimations on 25 clinically normal animals. The only significant sex difference detected was in the reticulocyte count which was higher in females than in males. The reference values were used to identify abnormal changes in the blood of nine clinical cases. Hypochromic anemia, neutrophilia, and raised fibrinogen levels were found in animals with self-inflicted injuries, dermatitis, and ileocecal intussusception. Target cells and jaundiced plasma were noted in a case of yersiniosis. Two animals in which generalized muscle wasting was the main abnormal clinical sign were severely anemic, and in one of these cases a significant number of Heinz bodies was present. The findings in these two animals were compared with those in common marmosets (Callithrix jacchus) with possible wasting marmoset syndrome.

Seasonal breeding in rhesus monkeys: Influence of the behavioral environment.

Abstract: The accepted model of breeding seasonality in rhesus monkeys states that females become reproductively active in response to an environmental cue and that males become sexually active in response to ovulating females. This model must be modified to include direct responses of the male to the physical environment, endocrine responses of males to sexual activity, and responses of the female to the sexual activation of fellow group members. The complex set of social stimuli that influences the breeding readiness of both sexes may serve to delimit more precisely the annual periods of conception and birth than would be the case if each individual responded only to the changing physical environment.