Birth spacing in langur monkeys (Presbytis entellus)

This paper presents 10 years of reproductive data on birth interval length and 5 years of data on reproductive behavior postpartum from a captive colony of gray langur monkeys (Presbytis entellus)housed in Berkeley, California. Birth intervals of females following different pregnancy and nursing schedules are compared. Females whose infants survive to the age of 9 months have a median birth interval of 15.4 months. The experimental separation of mothers from infants for a period of 2 weeks, 6 to 9 months postpartum, had no significant effect on the median birth interval length. Females experiencing a pregnancy failure or the loss of a neonate had median birth intervals of 9.6 and 10.7 months, respectively. These intervals were significantly shorter than the birth intervals of females whose infants survived to 9 months, showing that the presence of a nursing infant delays the female’s time to next conception by approximately 5 to 6 months. Females experienced a median of three estrous periods (two estrous cycles) before conceiving postpartum, regardless of pregnancy outcome or length of infant survival, and females rarely conceived during their first estrous period postpartum. Weaning did not occur until after the mother’s next conception. These data indicate that, in populations of langurs characterized by average birth intervals of 15 to 16 months, the loss of an infant after the age of 5 to 6 months will not accelerate a female’s ability to conceive or shorten the birth interval length. The available data on birth spacing from populations of free-ranging langurs are reviewed. It could not be demonstrated that non-Himalayan populations are characterized by birth intervals which are as long as 20 to 24 months. Rather, it is suggested that female langurs inhabiting seasonally arid sites, such as Jodhpur, Abu, and Dharwar, may be capable of producing infants on the average of every 15 to 16 months. Flexibility in the timing of births and the lack of well-defined birth seasons at these sites may be explained by this species’ dietary and digestive adaptations. Additionally, data on birth spacing and the age of missing infants from the above field sites, where it has been suggested that infanticide following changes in male leadership occurs habitually, do not lend support to the sexual selection hypothesis of infanticide as proposed by S. Hrdy (1974, 1977).     

Reproductive parameters of wild Trachypithecus leucocephalus: seasonality,infant mortality and interbirth interval

Understanding the reproductive parameters of endangered primate species is vital for evaluating the status of populations and developing adequate conservation measures. This study provides the first detailed analysis of the reproductive parameters of wild white‐headed langurs (Trachypithecus leucocephalus), based on demographic data collected over an 8‐year period in the Nongguan Karst Hills in Chongzuo County, Guangxi, China. From 1998 to 2002, a total of 133 live births were recorded in the population based on systematic censuses. Births occurred throughout the year, but the temporal pattern was highly correlated with seasonal variation in temperature and rainfall, with the birth peak coinciding with the dry and cold months of November–March. The average birthrate was 0.47±0.13 births per female per year and mortality for infants younger than 20 months was 15.8%. From 1998 to 2006, 14 females gave birth to 41 infants in four focal groups. The average age at first birth for female langurs was 5–6 years (n=5) and the interbirth interval (IBI) was 23.2±5.2 months (median=24.5 months, n=27). Infants are weaned at 19–21 months of age. The IBI for females with infant loss before weaning was significantly shorter than those for females whose infants survived. It appears that birth seasonality in the white‐headed langurs is influenced by seasonal changes in food availability. The timing of conceptions was found to coincide with peak food availability. The reproductive parameters for white‐headed langurs reported here are quite similar to those reported for other colobine species. One major difference is our observation of lower infant mortality in Trachypithecus. Am. J. Primatol. 71:558–566, 2009. © 2009 Wiley‐Liss, Inc.     

Reproductive parameters of wild female Rhinopithecus roxellana

On the basis on 6 years of observation, we estimated the reproductive parameters of a Golden snub-nosed monkey (Rhinopithecus roxellana) group in the Qinling Mountains, China. We observed 88 births in 47 females from 2001 to 2006. Two methods were used to calculate the birthrate. The first method is based on the number of births observed in a year, giving 0.49+/-0.07 (mean+/-SD), and the second method is based on the female-years of observation, giving 0.49+/-0.17 births per female per year in this troop. The mean interbirth interval is 21.88+/-6.01 months (mean+/-SD). The mortality of infant born between 2002 and 2005 was 22.4%. The interbirth intervals of females that had lost an infant before the age of 6 months were significantly shorter than that of females whose infants survived for more than 6 months. A female usually gives birth once every 2 years if the previous offspring survives to a weaning age of 5-6 months, or will give birth in the next year if the previous young dies before reaching an age of 6 months. Births were significantly concentrated during March to May of each year. The mean birth date was on April 14, median was April 12; and the standard deviation was 13.98 days. Birth peak occurs 6-7 months after mating peak. From observations on 15 individuals that gave birth for the first time, we concluded that the wild female Golden snub-nosed monkeys in Qinling Mountains start giving birth at an age of 5 or 6 years. We suggest that the seasonal reproductive pattern is an adaptive response to the availability of seasonal food. Our results are consistent with the hypothesis that these reproductive characteristics are a result of adaptation to the seasonality of mountain climate and food resources.     

Reproductive parameters in Guizhou snub‐nosed monkeys (Rhinopithecus brelichi)

In this study, we present data on reproductive parameters and birth seasonality of Guizhou snub‐nosed monkeys (Rhinopithecus brelichi). Our analyses are based on data from a small captive population collected over 15 years and on 5 years of observations of free‐ranging snub‐nosed monkeys. Captive females (n=4) mature at an age of 70.8±6.7 months and reproduce for the first time at 103.4±7.5 months. The mean interbirth interval was 38.2±4.4 months if the infant survived more than 6 months, which is longer than that in R. roxellana and R. bieti. In the wild and in captivity, births are very seasonal and occur only in a period from the end of March to the end of April. Our data suggest that population growth in Guizhou snub‐nosed monkeys is slow compared with the other two Chinese snub‐nosed monkey species. The risk of extinction is therefore particularly high in this species, given the small overall population size and slow population recovery potential. Am. J. Primatol. 71:266–270, 2009. © 2008 Wiley‐Liss, Inc.     

Pregnancy detection from fecal progestin concentrations in the red panda (Ailures fulgens fulgens)

The reproductive physiology of red pandas (Ailures fulgens fulgens) has not been well documented. This critically endangered species is not self‐sustaining in captivity despite several breeding populations, with low reproductive success and high infant mortality being leading causes of the decline. Hormone profiles were monitored in three groups of females (mated with birth, mated no birth, and not paired) to document pregnancy and parturition. Fecal samples were analyzed for progestins using a radio‐immuno assay. Females that gave birth had significantly higher progestins during the study period compared to females that mated and did not give birth and females that were not paired with a male. Two critical time frames were detected, Weeks 7–11 and Weeks 13–20, in which pregnant females could be differentiated from the others with a 95% confidence interval (CI). Detecting pregnancy in captive red pandas may assist animal care staff in management of the females and increase the survival rate of offspring. Zoo Biol 0:1–11, 2005. © 2005 Wiley‐Liss, Inc.     

Reproductive parameters over a 37-year period of free-ranging female Borneo orangutans at Sepilok Orangutan Rehabilitation Centre

We analysed the reproductive parameters of free-ranging female orangutans at Sepilok Orangutan Rehabilitation Centre (SORC) on Borneo Island, Sabah, Malaysia. Fourteen adult females produced 28 offspring in total between 1967 and 2004. The average censored interbirth interval (IBI) (i.e. offspring was still alive when mother produced a next offspring) was 6 years. This was shorter than censored IBIs reported in the wild but similar to IBIs reported for those in captivity. The nonparametric survival analysis (Kaplan-Meier method) revealed a significantly shorter IBI at SORC compared with wild orangutans in Tanjung Putting. The infant (0–3 years) mortality rate at SORC of 57% was much higher than rates reported both in the wild and captivity. The birth sex-ratio was significantly biassed toward females: 24 of the 27 sex-identified infants were females. The average age at first reproduction was 11.6 years, which is younger than the age in the wild and in captivity. The high infant mortality rate might be caused by human rearing and increased transmission of disease due to frequent proximal encounters with conspecifics around the feeding platforms (FPs). This young age of first reproduction could be because of the uncertainty regarding estimated ages of the female orangutans at SORC. It may also be affected by association with other conspecifics around FPs, which increased the number of encounters of the females with males compared with the number of encounters that would take place in the wild. Provision of FPs, which improves the nutritional condition of the females, caused the shorter IBI. The female-biassed birth sex-ratio can be explained by the Trivers and Willard hypothesis. The female-biassed sex ratio could be caused by the mothers being in poor health, parasite prevalence and/or high social stress (but not food scarcity) due to the frequent encounters with conspecifics around FPs.     

Reproductive efficiency of captive Chinese- and Indian-origin rhesus macaque (Macaca mulatta) females

Reproductive and survival records (n=2,913) from 313 Chinese-origin and 365 Indian-derived rhesus macaques at the Tulane National Primate Research Center (TNPRC) spanning three generations were studied. Least-squares analysis of variance procedures were used to compare reproductive and infant survival traits while proportional hazards regression procedures were used to study female age at death, number of infants born per female, and time from last birth to death. Chinese females were older at first parturition than Indian females because they were older when placed with males, but the two subspecies had similar first postpartum birth interval (1st PPBI) and lifetime postpartum birth interval (LPPBI). Females that gave birth to stillborn infants had shorter first postpartum birth intervals (1st PPBI) than females giving birth to live infants. Postpartum birth intervals decreased in females from age 3 to 12 but then increased again with advancing age. Chinese infants had a greater survival rate than Indian infants at 30 days, 6 months, and 1 year of age. Five hundred and forty-three females (80.01%) had uncensored, or true records for age at death, number of infants born per female, and time from the birth until death whereas 135 females (19.91%) had censored records for these traits. Low- and high-uncensored observations for age at death were 3 and 26 years for Chinese, and 3 and 23 years for Indian females. Uncensored number of infants born per female ranged from 1 to 15 for Chinese females and 1 to 18 for Indian females. Each of these traits was significantly influenced by the origin×generation interaction in the proportional hazards regression analyses, indicating that probabilities associated with age at death, number of infants born per female, and time from last birth to death for Chinese and Indian females did not rank the same across generations.     

Reproductive biology of female titi monkeys (Callicebus moloch) in captivity

Titi monkeys (Callicebus spp., Cebidae) are monogamous neotropical primates that live in family-like groups typically consisting of an adult monogamous pair and one or two young. Knowledge about the reproductive biology of this genus is scanty. This study investigated the reproductive biology of female dusky titi monkeys (Callicebus moloch). An initial analysis characterized reproductive parameters of 32 females from a captive colony maintained for 23 years at the California Regional Primate Research Center (CRPRC). The colony records provided data on reproductive parameters such as interbirth intervals, seasonality, age at first pregnancy, and reproductive rate in captivity. Changes in urinary levels of estrone conjugates (E1C) and pregnanediol-3alpha-glucuronide (PdG) were used to characterize major reproductive events. Urine samples from eleven females were collected during 17 months. The endocrine data were used to examine changes associated with cycling, conception, and the post-partum period as well as to determine the duration of the ovarian cycle and gestation length. The analysis of colony records indicated that females whose infant survived through weaning gave birth at intervals remarkably close to one year, while those who lost their offspring showed a significantly shorter interval. As long as they lived within the family group, mature female offspring did not breed. The analysis of the endocrine profiles indicated that after giving birth to a viable offspring, females undergo a relatively prolonged period of anovulation (approx. 6.5 months), followed by 1-3 non-conceptive cycles (approx. 1 month), after which they conceive and gestate (4.3 months).     

Litter size and infant survivorship in wild groups of cotton‐top tamarins (Saguinus oedipus) in Colombia

Cotton‐top tamains (Saguinus oedipus) are a critically endangered primate found only in Colombia. Efforts to conserve this species are centered on developing effective management plans that integrate biological information regarding population dynamics and factors that influence their survival. This study documented infants born to wild cotton‐top tamarin females from 1994–2008 at two distinct field sites in northern Colombia. Our studies have shown that wild cotton‐top tamarins typically give birth to one litter each year and infant survival to 6 months of age was greater in the wild than has been reported in captive colonies. However, similar to reports from captive colonies, litter size of wild cotton‐top tamarins ranges from 1–3 infants, with twin litters most common. Here we report the first occurrence of triplet litters in nearly 20 years of observing wild cotton‐top tamarin groups. Over the first 3 months of life, wild‐born infants exhibited highest mortality during the first week of life, similar to reports from captive colonies. Infant survival in the wild also increases with successive litters as it does in captivity. However, inter‐birth interval, group size, and the number of adult males in the group did not appear to influence infant survival in the wild. The value of such long‐term data from field studies aids in the information that can be used to model future population trends and develop effective conservation plans for this critically endangered primate. Am. J. Primatol. 71:707–711, 2009. © 2009 Wiley‐Liss, Inc.     

Reproductive capability of brushtail possums (Trichosurus vulpecula) transferred from the wilds of Brisbane, Adelaide, and Armidale into captivity in Brisbane

The transfer of animals from the wild into captivity is an important strategy for the conservation of species that are under threat of extinction. To determine the reproductive capability of animals following transfer from the wild, brushtail possums relocated from Brisbane, Adelaide, and Armidale into captivity in Brisbane were monitored. Seventy five percent of the Brisbane possums (N = 80) gave birth during the months from March to May following transfer from the suburbs of Brisbane and 75% of the young born reached weaning. Thirteen adult females and four adult male brushtail possums were relocated from Adelaide into captivity in Brisbane in June 1994. Four young were born in Brisbane, however none survived to weaning and all the relocated possums had died 2 years after their transfer from Adelaide. Seventeen adult females and seven adult male possums were transferred from Armidale to Brisbane in July 1996. In the first year, 1997, four young were born in Brisbane and none survived to weaning. In the second year, three young were born and survived to weaning. Two years after their transfer, one adult male and three adult females from Armidale and three juvenile possums were housed in the Brisbane enclosures. As the Brisbane, Adelaide, and Armidale possums received the same photoperiod and environmental conditions, some factor must have inhibited breeding activity in the Adelaide possums and to a lesser extent in the Armidale possums. The ability of the Armidale possums to give birth and wean their young after 2 years in Brisbane would suggest that relocated possums require up to 2 years in order to adjust sufficiently to their new environment to reproduce. However, the failure of the Adelaide possums to reproduce successfully after a similar period of time in Brisbane suggests that certain environmental differences inhibit the ability of different populations of possums to adjust to a new environment. J. Exp. Zool. 284:783-788, 1999. Copyright 1999 Wiley-Liss, Inc.     

Reproductive Parameters and Maternal Investment in Mandrills (Mandrillus sphinx)

We report on 14 years of reproductive data for semifree-ranging mandrills (Mandrillus sphinx) in Gabon, and we explore relationships between female rank, age and parity, and reproductive strategies. Most births (61% of 132) occurred during the wet season in Gabon, between January and March. Female rank and parity were unrelated to the timing of parturition. Gestation lengths average 175 days (SE = ±1 day; N = 61) and were similar irrespective of female rank, parity, or sex of offspring. Birth sex ratio did not differ significantly from unity (52% male), and was unrelated to maternal rank or parity. Stillbirths and neonatal mortality tended to be more common among lower-ranking females than among either mid-ranking or dominant females. Median age at first birth is 4.71 years, at a median body mass of 7.6 kg, ca 5 years before females attain their adult body mass (median 12 kg). Age at first reproduction is significantly correlated with dominance rank, with dominant females giving birth on average 1.3 years earlier than lower-ranking females do. Interbirth intervals (IBI) average 405 days (range 184–1159 days, N = 103), and are independent of the sex of the offspring. Infant death within 6 months shortened IBI to 305 days. Increasing age and parity are also associated with short IBI, as is higher rank. Maternal rank and parity appear to influence reproductive success in female mandrills, but there is no apparent differential maternal investment by sex.     

Birth seasonality and interbirth interval of captive Rhinopithecus bieti

This study, which is based on 10 years of birth records, shows that black-and-white snub-nosed monkeys (Rhinopithecus bieti) in captivity display marked birth seasonality. The birth season starts in December and ends in June, with a peak from March to May, and a median birth date of April 10. More male infants than female ones are born in captivity. More males were born at the Kunming Institute of Zoology (KIZ) than at the Kunming Zoo (KZ). Of 17 interbirth intervals (IBIs), 29% were from females that had lost an infant at <1 year of age or experienced stillbirth, and 71% were from females whose infant survived more than 1 year. The mean IBI for the former group (428+/-SD 87 days) was significantly shorter than that for the latter group (706+/-71 days), in agreement with reports of other Colobine species. Infant mortality was lower in captivity than in the field, which may reflect the relatively stable food availability and climate in captivity compared to the harsh conditions in the wild.     

Long-term effect of a simple nest-box on the reproductive efficiency and other life traits of an Aotus lemurinus lemurinus monkey colony: an animal model for malaria research

Background The long‐term effect of a PVC pipe nest‐box on the reproductive efficiency and other life traits of an Aotus monkey‐breeding colony have not been characterized. Methods and Results We analyzed laboratory records of the Gorgas Memorial Institute (GMI) Aotus monkey colony in Panama for the period 1999–2010 and found a 273% increase in the annual mean life births in the following 7 years after the introduction of a PVC pipe nest‐box in 2002, as well as increases in the mean body mass and survival of laboratory‐bred monkeys. Other life traits such as inter‐birth interval, parity, birth sex distribution, mortality, and longevity were also determined. Conclusions The use of a PVC pipe nest‐box significantly improved the reproductive efficiency and other life traits of the GMI Aotus breeding colony.     

Reproductive Parameters of Female<Emphasis Type="Italic">Pan paniscus</Emphasis> and <Emphasis Type="Italic">P. troglodytes</Emphasis>: Quality versus Quantity

We investigated intra- and interspecific differences in life history and reproductive parameters in bonobos (Pan paniscus) and chimpanzees (Pan troglodytes). We compare the parameters of wild and captive females in order to shed light on the influence of habitat or specific differences or both on reproduction. We present new and additional information on reproductive parameters from captive bonobos and chimpanzees. Captive chimpanzees birth more live offspring and have a shorter interbirth interval, but experience higher infant mortality than captive bonobos. Although captive bonobo females tend to start reproduction at a younger age than chimpanzees, this is effectively only so for wild-born females of both species. Ultimately both species reach the same rate of production of offspring surviving to 5 yr. These results contrast with data from the wild. Wild bonobos tend to have higher reproductive success, a higher fertility rate and a shorter interbirth interval than wild chimpanzees. Reproduction is similar for wild and captive bonobos, which suggests that they are producing at their maximum under both conditions. Overall captive chimpanzees perform better than their wild conspecifics, probably because of lower feeding competition. Infant survival is the only specific difference not affected by captivity. Bonobo infants survive better, which suggests that chimpanzee infants are more at risk. We argue that the interspecific variation in reproductive parameters in captivity is related to the different influence of captivity on reproduction and different pressures of external sources of infant and juvenile mortality.     

Calomys laucha (Rodentia, Cricetidae): growth and breeding in laboratory conditions

The husbandry and breeding of Calomys laucha (Rodentia, Cricetidae) in captivity are described. Growth curves based on body weight and length showed statistical differences between sexes after 45 days, males being heavier than females. The overall reproductive efficiency was 53.4% but birth rate was depressed during winter. Gestation length was 21 +/- 1 days and females exhibited postpartum oestrus with a 3-7 day implantation delay (51%). Litter size was 5.3 +/- 1.1 (n = 34). Pup survival at weaning was 84.9%. Mean life span in laboratory conditions was 13.5 months and a cumulative mortality of 90% was reached at 27-28 months of age.     

Fifty years of chimpanzee demography at Taronga Park Zoo

There has been a captive Pan troglodytes colony at Taronga Park Zoo in Sydney, Australia, since the mid-1930s. Demographic data on these animals were first analyzed in 1986; however, further information collected for 15 years since then is now available. The reproductive histories of 33 females in the colony have been recorded, and these data form the largest collection of captive chimpanzee data from a setting that has involved natural breeding conditions since the mid-1960s. These data were analyzed in conjunction with data from wild populations to establish the degree of variability present within chimpanzee reproductive parameters, and to identify which distinctive life history characteristics persist in well-provisioned, natural-fertility populations. The age at first birth for the chimpanzee females is 9.8 yr on average (n=16), which is 1-4.8 yr earlier than the average for wild populations. In line with this accelerated reproduction, birth intervals are also significantly shorter than those in noncaptive chimpanzee populations. The median birth interval for all surviving infants (based on a Kaplan-Meier survival analysis) is 49 months (n=43) compared to 62+ months for wild groups. At the same time, infant mortality remains high. The data confirm distinctive features of the life history of common chimpanzees, including later maturation, long birth intervals, a relatively invariant fertility schedule, and high juvenile mortality. However, aspects of both fertility and mortality are significantly related to social circumstances, indicating that in common chimpanzees, as in humans, life history characters may represent ecological and social adaptations rather than species-fixed characteristics.     

Comparative analysis of gonadal and adrenal activity in the black and white rhinoceros in North America by noninvasive endocrine monitoring

Patterns of fecal reproductive steroid metabolites and adrenal corticoids were characterized for 12‐ to 24‐month periods in black (n = 10 male, 16 female) and white (n = 6 male, 13 female) rhinoceroses at 14 institutions. All black rhinoceros females exhibited at least some ovarian cyclicity on the basis of fecal progestogen analysis (range, 2–12 cycles/yr). However, cycles often were erratic, with many being shorter (<20 days; 18% of cycles) or longer (>32 days; 21%) than the average of 26.8 ± 0.5 days (n = 104 cycles). Five females exhibited periods of acyclicity of 2–10‐month duration that were unrelated to season. One complete and seven partial pregnancies were evaluated in the black rhinoceros. Fecal progestogens increased over luteal phase concentrations after 3 months of gestation. Females resumed cyclicity within 3 months postpartum, before calves were weaned (n = 5). Approximately half of white rhinoceros females (6 of 13) showed no evidence of ovarian cyclicity. Of the cycles observed, 5 were “short” (32.8 ± 1.2 days) and 24 were “long” (70.1 ± 1.6 days). Only two females cycled continuously throughout the study. One had both long (n = 9) and short (n = 2) cycles, whereas the other exhibited long cycles only (n = 5). Fecal estrogen excretion was variable, and profiles were not useful for characterizing follicular activity or diagnosing pregnancy in either species. Males of both species showed no evidence of seasonality on the basis of fecal androgen profiles. Androgen metabolite concentrations were higher (P < 0.05) in the black (27.6 ± 6.9 ng/g) than in the white (16.8 ± 3.1 ng/g) rhinoceros. An adrenocorticotropin hormone challenge in four black rhinoceros males demonstrated that the clearance rate of corticoid metabolites into feces was ～24 hours. Fecal corticoid concentrations did not differ between males and females, but overall means were higher in the black (41.8 ± 3.1 ng/g) than in the white (31.2 ± 1.7 ng/g) rhinoceros. In summary, fecal steroid analysis identified a number of differences in hormonal secretory dynamics between the black and white rhinoceros that may be related to differences in reproductive rates in captivity. Most black rhinoceros females exhibited some cyclic ovarian activity. In contrast, few white rhinoceroses demonstrated evidence of regular estrous cyclicity, and those females that were active had comparatively long cycles. Results also suggest that fecal corticoid concentrations reflect adrenal activity and may be species specific. Continued studies are needed to determine whether fecal corticoid measurements will be useful for understanding the cause of inconsistent gonadal activity in these two species. Because all but three (15.8%) of the white rhinoceroses evaluated in this study were less than 20 years of age compared to 73.1% (19 of 26) of the black rhinoceroses, the impact of age on reproductive and adrenal activity also needs to be evaluated further. Zoo Biol 20:463–486, 2001. © 2002 Wiley‐Liss, Inc.     

Patterns of reproduction in Malayan silvered leaf monkeys at the Bronx Zoo

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.     

Reproductive performance in a breeding colony of Brazilian squirrel monkeys (Saimiri sciureus).

In a captive colony of Brazilian squirrel monkeys (Saimiri sciureus) a discrete birth season has been retained for 5 years although its duration increased from 3 months in 1972 to 6 months in 1976. The ages of breeder females in this colony ranged from 3 to 14 years, and within this range reproductive performance was not affected by age, although it was significantly better in feral than in colony-born females. The latter had a lower pregnancy rate and a higher incidence of neonatal and fetal deaths than did the feral monkeys. It is our belief that the reproductive and maternal capabilities of the colony-born females were adversely affected by the practice of removing neonates from their mothers at weaning and raising them with age-mates.     

Population dynamics of pedigree leopards,Panthera pardus ssp,in captivity

The demographic history of 4 races or subspecies of leopard, Panthera pardus, was reviewed from international studbook records dating back to 1953. The Chinese leopard has been the most common pedigree race maintained in captivity, a factor linked to the length of time (29 years) this subspecies has been in captivity. The relative youth of the wild-born founders also helped them to adjust to captivity as well as live long reproductive lives. Today, however, this race is suffering from the ill effects of inbreeding due to the small founder size. This condition appears to be correctable now that additional specimens have been located. Persian leopards have a larger founder size than the former race, but some of their ancestors were older animals at the time of acquisition. Because of this, their potential fecundity was probably depressed from psychological problems related to adjustment and a shorter life span in captivity. Two founding females experienced pelvic deformities while young, and few of their cubs survived because they all had to be delivered via caesarian section. This procedure also shortened the reproductive life of the females involved because the owning zoos refrained from breeding the animals in the leopards' later years. Captive leopards appear to live longer than their wild counterparts, although precise data on wild populations is not available. In captivity many reach 12–15 years old, and exceptional individuals of several races have lived 20 years. Most captive-born leopards begin breeding when they are 3 years old and continue until they are 8–10 years old. Reproduction in females usually ceases at 12–14 years, although males have a longer reproductive life, with several successfully breeding when 19–20 years old.