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.     

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 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 captive alpine ibex (Capra i. ibex)

We studied the reproductive biology of alpine ibex bred at the Peter & Paul Wildlife Park, St. Gallen, Switzerland, from 1930 through 1943 and 1968 through 1983. Peter & Paul Wildlife Park had supplied most of the original stock used to reestablish ibex populations in the European Alps after they had become extinct. Ibex females were seasonally polyestrous. Their estrous cycle averaged 20 days, and their gestation period averaged 167 days. Females between 1 and 15 years of age on average produced 0.78 young per year; females between 3 and 13 years of age produced 0.99 young per year. The average age at which captive ibex females gave birth was 8.44 years. Sex ratio at birth was unbiased. More singletons than twins were born, but the proportion of twins born during the years 1968 through 1983 was higher than during the earlier study period. There were no differences in the survival rates of male or female and single or twin offspring.     

Influence of daylength on the initiation of the breeding season of the marsupial possum, Trichosurus vulpecula

In Queensland, possums in the wild and in captivity first give birth during March and continue to give birth throughout the year until November. In this study the effect of short daylengths on the initiation of breeding activity was examined. One male and 4 female possums were transferred from an outside enclosure into a light control room (10 h light, 14 h dark) on 22 November. A control group of possums was housed in outside enclosures. The possums held in the light room gave birth 81.2 +/- 14.7 days (s.e.m.) after being placed in the short-day photoperiod. The control group gave birth 133.8 +/- 9.8 days after 22 November. This result suggests that photoperiod plays a role in the initiation of the breeding season of the brushtail possum.     

Demography of captive Asian elephants (Elephas maximus) in southern India

Historically, the Asian elephant has never bred well in captivity. We have carried out demographic analyses of elephants captured in the wild or born in captivity and kept in forest timber camps in southern India during the past century. The average fecundity during this period was 0.095/adult female/year. During 1969–89, however, the fecundity was higher at 0.155/adult female/year, which compares favorably with wild populations. There was seasonality in births with a peak in January. The sex ratio of 129 male to 109 female calves at birth is not significantly different from equality, although the excess of male calves born mainly to mothers 20–40 years old may have biological significance. Mortality rates were higher in females than in males up to age 10, but much lower in females than in males above age 10 years. The population growth rate, based on the lower secundity over the century, was 0.5% per year, and based on the higher secundity during 1969–89, was 1.8% per year. The analyses thus showed that timber camp elephants in southern India could potentially maintain a stationary or increasing population without resorting to captures from the wild. Breeding efforts for elephants in zoos can thus profitably learn from the experience of traditional management systems in part of Asia. Zoo Biol 16:263–272, 1997. © 1997 Wiley-Liss, Inc.     

Reproduction of the quokka, Setonix brachyurus, in captivity

This study records estimations of the chronology of certain events in the calendar of development of the quokka. One gestation period of between 25 and 26 days was observed and 22 joeys (young) had an average birth weight of 0.3852±0.0436 g. Vacation of the pouch occurred between 185 and 195 days of age. One thousand joeys were found to have a masculinity of 0–453 which is statistically smaller than parity. An estimation was made of the age at which the separate teeth erupt and a method of approximating the ages of juveniles and yearlings proposed by using dental eruption stages. The youngest recorded ages at which males and females became reproductively mature were 389 and 252 days respectively. After attaining reproductive maturity all animals born in captivity bred throughout the year. Animals taken from Bald Island, although showing seasonal breeding in the wild, will breed without periodic anoestrus interruption when taken into captivity. Captive animals may live seven years or longer. Using the chronology of some of the above events a comparison was made of the reproductive potential of the wild and domesticated populations.     

Reproduction and population growth in free-ranging mantled howling monkeys

Free-ranging mantled howling monkey (Alouatta palliata Gray) females experienced a regular estrus cycle averaging 16.3 days, demonstrated sexual skin changes, and participated in multiple matings before becoming pregnant. Gestation averaged 186 days. The average interval between births was 22.5 months. Sexual maturity occurred at approximately 36 and 42 months for females and males, respectively. Female age at first birth was about 3½ years. Births were scattered during some years and clustered during others. The age, rank, and parity of the females affected infant survival. More female than male infants survived to one year of age. Increased population size was the result of immigration rather than births.     

Reproductive parameters of female Japanese macaques: Thirty years data from the arashiyama troops,Japan

Over a 30-year period from 1954 to 1983, 975 live births were recorded for Japanese macaque females at the Iwatayama Monkey Park, Arashiyama, Japan. Excluding unknown birth dates, primiparous mothers gave birth to 185 infants (182 cases with age of mother known) and multiparous mothers gave birth to 723 infants (603 cases with age of mother known). The peak month of birth was May with 52.3% of the total births occurring during the period. Multiparous females who had not given birth the previous year did so earlier than multiparous females who had given birth the previous year and also earlier than primiparous females. Among the females who had given birth the previous year, females whose infant had died gave birth earlier than females who had reared an infant the previous year. The offspring sex ratio (1:0.97) was not significantly different from 1:1, and revealed no consistent association with mother's age. Age-fecundity exhibited a humped curve. The annual birth rate was low at the age of 4 years but increased thereafter, ranging between 46.7% and 69.0%, at between 5 and 19 years of age, but again decreased for females between 20 and 25 years of age. Some old females displayed clear reproductive senescence. The infant mortality within the first year of age was quite low (10.3%) and the neonatal (less than 1 month old) mortality rate accounted for 49.0% of all infant deaths. There was no significant difference between the mortality rates of male and female infants. A female's rank-class had no apparent effect on the annual birth rate, infant mortality, and offspring sex ratio. These long-term data are compared with those from other primate populations.     

A retrospective study of infant mortality of cotton-top tamarins (Saguinus oedipus) in captive breeding

Fifty of 156 (32%) colony bred cotton-top tamarins were stillborn, and 31 (20%) died within the first week after birth. The stillbirth rate was related to litter size and parity in captivity. A higher percent of single births were stillborn (69%) compared to those of twin births (26%) (p less than 0.005). A higher percent of infants born of the first litter in captivity (42%) were stillborn than those of subsequent litters (23%) (p less than 0.025). Stillbirths were not related to season of birth or sex of infant. Survival of live infants was unrelated to season of birth, sex, litter size, or number of litters.     

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.     

Catch-up growth in females born short for gestational age reduces the risk of giving birth to short-for-gestational-age infants

OBJECTIVES: The aim of the present study was to study the effect of catch-up growth on the offspring's length at birth among females born short for gestational age. METHODS: Data of 1,363 females born short for gestational age (<-2 standard deviation scores) were obtained from the Swedish Birth Register. The females were included in the register both as babies and mothers. The effect of catch-up growth on the offspring's birth length was studied. RESULTS: Short adult stature was associated with a threefold increase in the risk of giving birth to a short infant [OR 3.08 (CI 1.73-5.50)] and smoking increased the risk in a dose-dependent manner. Overweight was associated with a reduced risk [OR 0.46 (CI 0.22-0.96)] of giving birth to a short infant. CONCLUSION: Catch-up growth to normal adult stature among women born short for gestational age is associated with a reduced risk of giving birth to a short-for-gestational-age infant.     

Reproduction in captive female Cape porcupines (Hystrix africaeaustralis)

Captive females attained sexual maturity at an age of 9-16 months and conceived for the first time when 10-25 months old. Adult females were polyoestrous but did not cycle while lactating or when isolated from males. The length of the cycle varied from 17 to 42 days (mean +/- s.d. 31.2 +/- 6.5 days; n = 43) and females experienced 3-7 sterile cycles before conceiving. Pregnancy lasted for 93-94 days (93.5 +/- 0.6 days; N = 4) and litter intervals varied from 296 to 500 days (385 +/- 60.4; n = 10). Litter size varied from 1 to 3 (1.5 +/- 0.66; n = 165) and the well-developed precocial young weighed 300-440 g (351 +/- 47.4 g; n = 19) at birth. Captive females reproduced throughout the year with most litters (78.7%; n = 165) being produced between August and March.     

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.     

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.     

Suckling behaviour in the brown long-eared bat (Plecotus auritus)

Thirty-two adult female brown long-eard bats were taken into captivity. Eight individuals gave birth to single young in captivity (known mother-young pairs), 10 were lactating when captured (putative mother-young pairs), and the remaining 14 bats were non-reproductive. Bats were maintained in five groups consisting of females from sigle(n=3) or mixed (n=2) wild roosts. All bats were housed in outdoor, free-flight enclosures and fed mainly on free-flying noctuid moths. Bats were individually were determined daily (n=152) for a single gruup of bats containing four known mother-young pairs and five non-reproductive bats. The probability of a being attached to the nipple declined from 100% of records at 1-5 days of age to 5% of records at 36-40 days of age. Females were always found suckling their own young. Suckling associations were determined using infra-red sensitive video-recordings of bat behaviour within the roost box. For both known (n=8) and putative mother-young pairs (n=10), there were no records of young attached to lactating females other than their own mothers (from the same or different wild roosts).     

The effects of dominance rank and group size on female lifetime reproductive success in wild long-tailed macaques,Macaca fascicularis

Demographic changes were recorded throughout a 12-year period for three social groups ofMacaca fascicularis in a natural population at Ketambe (Sumatra, Indonesia). We examined the prediction that females' lifetime reproductive success depended on dominance rank and group size. Average birth rate was 0.53 (184 infants born during 349 female years). For mature females (aged 8–20 yr) birth rate reflected physical condition, being higher in years with high food availability and lower in the year following the production of a surviving infant. High-ranking females were significantly more likely than low-ranking ones to give birth again when they did have a surviving offspring born the year before (0.50 vs 0.26), especially in years with relatively low food availability (0.37 vs 0.10). Controlled comparisons of groups at different sizes indicate a decline in birth rate with rroup size only once a group has exceeded a certain size. The dominance effect on birth rate tended to be strongest in large groups. Survival of infants was rank-dependent, but the survival of juveniles was not. There was a trend for offspring survival to be lower in large groups than in mid-sized or small groups. However, rank and group size interacted, in that rank effects on offspring survival were strongest in large groups. High-ranking females were less likely to die themselves during their top-reproductive years, and thus on average had longer reproductive careers. We estimated female lifetime reproductive success based on calculated age-specific birth rates and survival rates. The effects of rank and group size (contest and scramble) on birth rate, offspring survival, age of first reproduction for daughters, and length of reproductive career, while not each consistently statistically significant, added up to substantial effects on estimated lifetime reproductive success. The group size effects explain why large groups tend to split permanently. Since females are philopatric in this species, and daughters achieve dominance rank positions similar to their mother, a close correlation is suggested between the lifetime reproductive success of mothers and daughters. For sons, too, maternal dominance affected their reproductive success: high-born males were more likely to become top-dominant (in another group). These data support the idea that natural selection has favored the evolution of a nepotistic rank system in this species, even if the annual benefits of dominance are small.     

Mortality rate of Japanese twins: Infant deaths of twins after birth to one year of age

Abstract

In twin individuals born in Japan in the first half of 1974, rates of infant mortality up to one year of age were computed according to sex and order of birth. The rates were 5.50 per cent for males and 3.81 per cent for females. A lower mortality rate for first‐born twins indicates a reduced viability for second‐born twins, even in MZ twins. The effect of maternal age, gestational age, and birth weight on the rates of infant mortality were also analyzed.