Color changes in the haircoat of patas monkeys (Erythrocebus patas)

Caged patas monkeys were evaluated monthly to determine changes in the color of their hair during infancy, adolescence, pregnancy and lactation. From birth until 3 months of age the facial and anterior crown hairs were short, sparse, and completely black. The body fur was a fine, short, fawn-colored hair mixed with longer black hairs which produced a black-tipped effect. During the second 3 months of life the body fur and anterior crown fur became coarser, longer, and changed to a red-brown color. The facial hairs thickened and became longer, but remained totally black. A thin line of black hairs outlined the brow and temple. The black chin hairs were gradually replaced by white from 7 to 24 months of age, and the upper lip hairs changed from black to white during the second year of life. Color changes related to pregnancy and lactation were confined to the nosepatch, cheek, and browline hair. The nosepatch and cheek hair changed from black or grey to completely white, and the browline faded to the approximate color of the body fur. These changes began approximately at the end of the second trimester of pregnancy, maximized during the third month of lactation, began to darken 1 to 2 months later, and returned completely to the black, nonpregnant colors approximately 1 year postpartum. In one nonlactating female, the darkening was delayed until 500 days postpartum and in one female ovariectomized in the light color phase, the darkening was complete 200 days later. The cause of these changes is believed to be hormonal, resulting from altered endocrine function during maturation and pregnancy, which may alter melanocyte stimulating hormone activity.     

Reproductive performance of a laboratory breeding colony of patas monkeys (Erythrocebus patas)

Reproductive statistics were gathered over a 5½-year period on a colony of Erythrocebus patas. Pregnancies occurred throughout the year under laboratory conditions with a suggestion of a mating peak in the late fall and early winter. Menstrual cycles were monitored and found to average 30.6 days in length. Maximal vaginal cornification occured on day 15 of the cycle suggesting a midcycle ovulation. However, production of timed-mated pregnancies indicated ovulation occurred earlier and that breeding on days 10, 11, and 12 after menstruation was more likely to result in pregnancy. The gestation length was found to average 167.2 days in 142 harem-bred females and 167.5 days in 11 timed-mated pregnancies. Sixty-two percent of all pregnancies resulted in live births; 28% of the conceptions terminated with in-utero death of the fetus. Stillborn infants were delivered in 9% of the pregnancies. Infant mortality during the first 6 months of life was 10.2%. Females raised in the colony conceived their first offspring at approximately 3 years of age and males were able to sire infants at 3 years and 8 months.     

Influence of age,sex, and caging on joint mobility in the patas monkey (Erythrocebus patas)

Normal range of joint mobility in the extremities of the patas monkey, Erythrocebus patas, was established for a free-ranging colony of 64 animals at La Parguera, Puerto Rico (Caribbean Primate Research Center). Eighty-five animals that had been caged (30″ × 30″ cages) for up to 5 years were used for comparison. Passive joint mobility of anesthetized animals was measured with a goniometer. Nine parameters (five on the forelimb and four on the hindlimb) were measured on each animal. The data were sorted into subsets according to the animal's age, sex, place of birth, and type of confinement, if any. The number of animals in each subset was recorded and the mean (in degrees) and standard deviation for each parameter were calculated. A P?0.05 on two-tailed Student's t-tests was considered significant. Comparisons between free-ranging males and females showed significant differences in one or two parameters for all age groups. A cross-sectional sample of free-ranging animals of both sexes showed that significant changes in joint mobility occurred only in the first 18 months of life. Joint mobility of all caged animals, however, was highly variable, and even between the more mature animals there were significant differences in several parameters. Almost all comparisons of subsets of the same age and sex showed significant differences between caged and free-ranging animals in at least one parameter. When the caged animals were laboratory-born, however, these differences were significant in five out of nine parameters. The results suggest that, although caging itself affects joint mobility, the age of first confinement may have an even greater effect than the length of the confinement.     

Patterns of mating among male patas monkeys (Erythrocebus patas) in Kenya

An habituated group of wild patas monkeys was observed in Kenya for 550 h in 1984. Observations were made primarily during an interval that, as previous studies at the same site had demonstrated, coincided with the annual mating and conception periods. Earlier field studies of patas at other sites had reported that heterosexual patas groups had only a single resident adult male and that mating was harem-polygynous. At the Kenya site, by contrast, as many as six males were simultaneously resident and mated in the group during the conception period. Males adopted a variety of tactics to gain access to receptive females, ranging from opportunistic mating to attempts at sequestration that resembled consort behavior in other cercopithecoids such as savanna baboons and rhesus macaques. Aggressive competition for access to females took place among the males, although the number of completed copulations per male did not bear a positive relation to agonistic dominance rank. For patas monkeys, harem polygyny is only one available option within an overall mating system that is best described as a form of promiscuous polygyny, especially during periods when conception is most likely.     

Passive joint mobility in patas monkeys (Erythrocebus patas): rehabilitation of caged animals after release into a free-ranging environment

A previous study of passive joint mobility in patas monkeys (Erythrocebus patas) showed that laboratory-caged animals had significantly greater mobility in most joints than age/sex matched free-ranging monkeys. Passive joint mobility on 27 of the same animals was measured 6 months after the caged animals were released onto a 40-hectare island. The results show that within 6 months of becoming free-ranging, typical passive joint mobility is restored. Thus, although caging directly affects measurements of morphologically-determined features in patas monkeys, confinement itself does not necessarily prevent rehabilitation if the immature monkeys are released into a free-ranging environment.     

Schistosoma intercalatum Fisher, 1934 (Cameroon) infection in the patas monkey (Erythrocebus patas Schreber, 1775).

Kuntz R. E., McCullough B., Huang T. C. and Moore J. A. 1978. Schistosoma intercalatum Fisher, 1934 (Cameroon) infection in the patas monkey (Erythrocebus patas Schreber, 1775). International Journal for Parasitology8: 65–68. Patas monkeys (Erythrocebus patas) have been infected with Schistosoma intercalatum, a schistosome of increasing concern in Africa, to study definitive host-parasite relationships. A high compatibility for parasitism in the S. intercalatum-patas monkey system was demonstrated suggesting this combination for long-term investigations in which minimal parasite destruction by the host would be expected. Egg production by S. intercalatum was high. Most eggs are deposited in the large intestine, but they elicit only slight pathology. No pathologic involvement of the urinary bladder was observed, in contrast to previous investigations in which other species of nonhuman primates infected with S. intercalatum developed extensive pathology.     

Life-history parameters of a wild group of West African patas monkeys (Erythrocebus patas patas)

Based on long-term, although intermittent, observations (2 years 4 months of 14 years), we present data on birth seasonality, age at first birth, interbirth intervals, mortality rates, age at first emigration, and population change of a wild population of West African patas monkeys (Etythrocebus patas patas) in northern Cameroon. Birth season was from the end of December until the middle of February, corresponding to the mid-dry season. In spite of large body size, the patas females had the earliest age at first birth (36.5 monthsold) and the shortest interbirth intervals (12 months) compared to the closely related wild forest guenons. Age at first emigration of the males was considered to occur between 2.5 and 4.5 years. The group size of the focal group drastically decreased between 1984 and 1987, and steadily increased until 1994, then decreased again in 1997. The neighboring group also showed a similar trend in group size. The population decreases were likely to be caused by drought over 3 years. Annual crude adult mortality rate was 4% during population increase periods (PIP) between 1987 and 1994. It rose to 22% during all the periods (AP), including drought over 3 years. Despite their smaller body size, the rate of the wild forest guenons (Cercopithecus mitis) (4%) was the same and much lower than those of the patas during PIP and AP, respectively. The annual average juvenile mortality rate was 13% during PIP and it also rose to 37% during AP. That of wild forest guenons (C. ascanius) (10–12%) was a little lower and much lower than those of the patas during PIP and AP, respectively. These findings were consistent with Charnov's theoretical model of mammalian life-history evolution in that patas with high adult and juvenile mortality showed early and frequent reproduction in spite of large body size. Charnov also considered high adult mortality as a selective force and high juvenile mortality as a density-dependent consequence of high fecundity. Our results support the former but not the latter research findings.     

Comments on oral grooming by patas monkeys,including a comparison with rhesus macaques

Observations of the motor patterns used by patas monkeys during allogrooming indicate that this species uses oral movements much more than previously believed. Compared to rhesus macaques, patas show more mouthpicks and licks, and fewer handpicks. Despite behavioral and anatomical evidence for good precision gripping, patas usually remove debris from a partner's fur orally rather than manually.     

Longitudinal study of dominance relations among captive patas monkeys

Eight and a half years of dominance relations within a captive group of patas monkeys were analyzed. It was found that matrilineal kinship significantly influenced individuals' ranks. In contrast, with the exception of certain intramatriline changes, increasing age had no predictable effect on overall rank, at least for females (this was untestable for males). Offspring typically challenged maternal dominance and in eight of twelve dyads, offspring either rose fully over their mothers (three cases, all daughters) or at least achieved dominance ambiguity with them. Additionally, two of the four younger sisters with an opportunity to rise in rank over an older sister did so. The group dominance hierarchy was unstable for 75% of the study due to a combination of agonistically induced and demographically induced rank changes. Concentration of the highest ranks in a single matriline showed a stronger association with group hierarchy stability than did the presence of an adult, nonnatal male. Group hierarchy stability was associated with increased affiliation (sitting close and sitting touching), but otherwise there were no behavioral correlations. Individuals' ranks within the group hierarchy were unrelated to their chances of being wounded or having diarrhea. Adult females' ranks were over twice as stable as the group hierarchy (57.1% stability), but stability/instability was not correlated with any behavioral changes. Available evidence suggests that dominance relations play only a minor role in the organization of patas monkeys' intragroup behavior. Am. J. Primatol. 42:41–51, 1997. © 1997 Wiley-Liss, Inc.     

Male Demography,Female Mating Behavior,and Infanticide in Wild Patas Monkeys (Erythrocebus patas)

Infanticide by males has been hypothesized to be a naturally selected behavioral strategy that increases the infanticidal male's reproductive success. The sexual selection hypothesis has been challenged via alternative, nonadaptive hypotheses that dispute its empirical and theoretical bases. Two of the most widely recognized alternatives are the social pathology hypothesis, in which infanticide results from overcrowding or recent human disturbance, and the generalized aggression hypothesis, in which infanticide is an epiphenomenon of increased male aggression. We report the first case of infanticide in wild, seasonally breeding patas monkeys (Erythrocebus patas) living at a low population density in a stable habitat, conditions which do not support the social pathology hypothesis. Its exceptional occurrence is consistent with the sexual selection hypothesis: over a 7-year period the infanticidal male was the only one of 13 resident males that was not present during the actual conception season but was present during the following birth season. Also consistent with this hypothesis, mothers were differentially targeted for male aggression, which increased sevenfold during the days surrounding the infanticide and then decreased to baseline levels after the infanticide. Aggression targeted at mothers does not support the generalized aggression hypothesis. As predicted by the sexual selection hypothesis, females began soliciting mating immediately after the infanticide, despite its occurrence in the nonconceptive season.     

Mating strategy and reproductive success of male patas monkeys (Erythrocebus patas)

Mating behavior and paternity of offspring of wild patas monkeys were studied at Kala Maloue National Park, Cameroon. Observation of patas groups over three years revealed that multi-male situations occurred after takeover of the position of a resident male. Direct observation of behavior showed that resident males (harem males) occupied only 31% of mating in multi-male situations and 100% in one-male situations. DNA-typing revealed that resident males sired two of four of infants in the one-male situation and four of five in the multi-male situation. Under the two years cycle of the one-male situation and the multi-male situation, calculation shows that resident males sired more offspring than sneakers both in observation and paternity testing. Sneak mating occurred during both one-male and multi-male situations, and resident males performed compensatory mating, with dilution of sneaker sperm; these activities explain the discrepancy found between observation of mating and results of paternity discrimination.     

Patas monkey copulations: One mount,repeat if necessary

Early, anecdotal reports of patas monkey (Erythrocebus patas) sexual behavior suggested that these primates were series-mount copulators. In 1975, limited evidence was presented in favor of single-mount copulations as the species-typical pattern for patas. The situation remained confused, however, as indicated by statements in a recent review article. This paper adds to our knowledge of patas sexuality by presenting quantitative data on the copulatory behavior of two additional adult males. Both males usually gave pelvic thrusts to intravaginal ejaculation once they had mounted a female and gained intromission. Mounts without ejaculation were clearly failed attempts at copulation, rather than segments of a stereotyped series-mount pattern. All of the available quantitative data indicate that the species-typical mating pattern for patas monkeys is copulation in a single mount.     

An assessment of dominance and kinship among patas monkeys

Kaplan andZucker (1980) argued that dominance and kinship do not function as important organizing features for intragroup behavior and social structure among patas monkeys (Erythrocebus patas). This paper reviews the available data pertinent to this argument and concludes that dominance probably is not a reliable structural variable for captive patas, despite its clear development in most groups. In contrast, kinship is a major organizing feature that strongly affects allogrooming and other affiliative interactions, and socialization.     

Naturally occurring Yersinia enterocolitica septicemia in patas monkeys (Erythrocebus patas)

Two cases of Yersinia enterocolitica septicemia occurred in a breeding group of 22 adult patas monkeys (Erythrocebus patas). Affected animals had acute clinical signs of depression, weakness, dehydration, hypothermia, hepatomegaly and pronounced leukopenia. Both animals died a few hours after treatment was initiated. Gross necropsy findings included jaundice, fluid in body cavities, hepatomegaly, splenomegaly, multiple white foci within the liver and spleen, generalized lymph node enlargement and numerous mucosal ulcerations in the colon. Primary histopathological lesions were multifocal hepatic necrosis, splenic necrosis, chronic ulcerative enteritis and diaphragmatic myositis with necrosis and edema. Yersinia enterocolitica was cultured from the liver, spleen, lung, jejunum and rectum. Wild rodents, particularly mice, may have been a source of infection for these animals, as the monkeys were housed in a rural, indoor-outdoor facility. A preliminary culture survey showed that some clinically normal patas monkeys harbored the organism in their intestinal tracts.     

Observations of parturition among captive patas monkeys (Erythrocebus patas)

Six cases of labor and delivery by laboratory-housed patas monkeys (Erythrocebus patas) are described. Five of the births occurred during the daytime, and the sixth occurred just after the usual “lights out” time. Although it was impossible to determine the actual onset of labor, the final 1.5–0.5 hr before parturition were observed in all cases. Throughout labor, females tended to begin a contraction every 2–4 min and contractions usually lasted 35–60 sec. Females did not show common patterns of change in contraction frequency or duration as birth neared. It was not possible to describe patas monkey labor and delivery in terms of “stages.” Postpartum, females typically began cleaning their infants within 90 sec and picked them up within 5 min. Placental delivery times varied among females, as did the extent of placental consumption. One “mother-only” - reared female proved to be an inadequate mother.     

Growth and hematologic development of the patas monkey (Erythrocebus patas) to one year of age.

Data from 338 blood samples of 31 patas monkeys is presented to show the normal hematolgoic development from birth to one year of age, and is compared to 120 samples from normal adults. Marked changes in hematocrit, hemoglobin, red cell numbers, and leukocyte distribution which occurred during the first month were followed by a slow progression to adult values. Body weight data is also presented which shows a linear growth rate during the first year of life.     

Dental eruption sequence and eruption times in Erythrocebus patas

Erythrocebus patas has a short inter-birth interval, juveniles become independent from their mother early, females are young at first birth, and adult females have a high mortality rate. According to Schultz’s rule, the molars of fast-growing and shorter-lived primate species erupt early relative to the replacement teeth. Based on the life history of E. patas, we hypothesized that the molars would erupt before the replacement teeth and/or that the eruption time of its molars would be early. The purpose of the present study was to determine the dental eruption sequence and eruption times for E. patas and to test our hypothesis. The eruption sequence for the permanent teeth of E. patas is \frac\textM1  \textI1  \textI2  \textM2  \textP3  \textP4  [\textC  \textM3]\textM1  \textI1  \textI2  \textM2  \textP4  [\textP3  \textC]\textM3 \frac{{{\text{M1}}\;{\text{I1}}\;{\text{I2}}\;{\text{M2}}\;{\text{P3}}\;{\text{P4}}\;[{\text{C}}\;{\text{M3}}]}}{{{\text{M1}}\;{\text{I1}}\;{\text{I2}}\;{\text{M2}}\;{\text{P4}}\;[{\text{P3}}\;{\text{C}}]{\text{M3}}}} in males and \frac\textM1  \textI1  \textI2  [\textM2  \textP4  \textP3  \textC]\textM3\textM1  \textI1  \textI2  [\textM2  \textP4  \textP3  \textC]\textM3 \frac{{{\text{M1}}\;{\text{I1}}\;{\text{I2}}\;[{\text{M2}}\;{\text{P4}}\;{\text{P3}}\;{\text{C}}]{\text{M3}}}}{{{\text{M1}}\;{\text{I1}}\;{\text{I2}}\;[{\text{M2}}\;{\text{P4}}\;{\text{P3}}\;{\text{C}}]{\text{M3}}}} in females. Because these sequences constitute the general pattern seen in cercopithecines, Schultz’s rule could not be applied to E. patas. The emergence time of upper and lower first molar (M1) is earlier in E. patas than in macaques, baboons, and mandrills and is similar to that in Chlorocebus aethiops. The emergence time of deciduous upper and lower fourth premolar (dp4) is similar to that in the above-mentioned cercopithecines but is later than that in Ch. aethiops. The emergence times of upper and lower second molar (M2) and upper and lower third molar (M3) in E. patas are earlier than those in the above-mentioned cercopithecines but later than those in Ch. aethiops. However, the intervals of the emergence time between each permanent molar in E. patas are similar to those of the above-mentioned cercopithecines. The early appearance of M2 and M3 in E. patas is related to the short interval of emergence time between dp4 and M1.