Assessing reproductive profiles in female brown mouse lemurs (Microcebus rufus) from Ranomafana National Park,southeast Madagascar,using fecal hormone analysis

Studies on reproductive endocrinology in wild primate populations have greatly increased in the last decades owing to the development of noninvasive techniques that can be applied under field conditions. However, small‐bodied nocturnal species are not well represented on the long list of primates surveyed in the wild, and reproductive inferences regarding these animals in their natural habitats have not benefited from direct observations of hormonal changes. We collected fecal samples from female brown mouse lemurs (Microcebus rufus) in a southeastern rainforest of Madagascar in order to determine whether or not fecally excreted steroid levels show a consistent pattern of change during the reproductive season and are a useful complement to reproductive observations in wild‐trapped individuals. Initial data show variation in reproductive hormone levels before and after estrus and estimated day of parturition. Elevated levels of excreted estradiol (E₂) were observed around the time of estrus, whereas high levels of fecal progesterone (P) were seen during later stages of pregnancy and around parturition. A more complete picture of reproductive profiles in female mouse lemurs, and how they may change over the life span, can be obtained if hormone analyses are used to supplement field observations. Am. J. Primatol. 71:439–446, 2009. © 2009 Wiley‐Liss, Inc.     

Comparison of Reproductive Characteristics and Changes in Body Weight Between Captive Populations of Rufous and Gray Mouse Lemurs

The nocturnal Malagasy mouse lemurs are among the smallest primates worldwide. Several sibling species are known. Of these, the rufous and the gray mouse lemur differ with respect to morphology, genetics, and communication. They might also differ in seasonal reproduction and body weight changes. We investigated and compared reproductive activities and changes in monthly body weight in males and females of successfully breeding colonies of both species under the same photoperiodic conditions. Females of both species showed estrous cycles only during the long-day period. Rufous mouse lemur females seemed to have a shorter gestation than their sibling species (57 vs. 62 days). The number of estrous cycles (2.25 vs. 2.5/season) and their lengths (59 vs. 52 days) were similar. Litter size (2) seemed to be similar. Latency of estrous occurrence after photoperiodic stimulation was longer in Microcebus rufus than in its sibling species (71.6 and 42.3 days). The same was true for the onset of the growth of the testes. The rate of growth and size of the testes were similar, and precede the estrous onset in both species. The reproductive activity was shorter in both sexes of the rufous than of the gray mouse lemurs. In both species, body weight showed similar seasonal changes. Males lost more weight during the breeding season than females did. In rufous mouse lemurs, body weight was similar in both sexes during the nonbreeding season. In gray mouse lemurs, sexes differed throughout the year.     

Timely estrus in wild brown mouse lemur females at Ranomafana National Park, southeastern Madagascar

The small-bodied nocturnal mouse lemurs (genus Microcebus) occupy a variety of habitats in Madagascar. Gray (M. murinus) and brown (M. rufus) mouse lemurs have been widely studied both in the wild and captivity. Whereas captive studies revealed an endogenous regulation of reproduction entrained by photoperiod, field studies have suggested that reproductive activation could be affected by additional climatic, physical, or social conditions. I collected data on wild brown mouse lemur females at Ranomafana between 2004 and 2008 to determine: 1) the timing of estrus and estrous periodicities across multiple seasons, and 2) whether additional factors such as body mass, age, or rainfall are correlated with onset of reproduction. In mouse lemur females at Ranomafana, the first seasonal estrus occurs 3-4 weeks after the vernal equinox. I report ~1 month's intra-population variation in the timing of estrus and inter-annual estrous intervals with periodicities of ~365 days. There were significant differences between the onset of reproduction across years. Estrous onset was uncorrelated with body mass, but there was an apparent age effect. There was a significant negative correlation between August rainfall and onset of reproduction when 2004 data were removed from the analysis. Results from this study are consistent with the notion that timing of estrus is photoperiod-dependent. As in captivity, intra-population variation in estrous onset is ~4 weeks in length. In the wild, variation in estrous onset and polyestry (multiple reproductive opportunities per year) appear to be favored under the highly unpredictable conditions of Madagascar's environments. In the wild, variation in estrous onset and polyestry (multiple reproductive opportunities per year) appear to be favored under the highly unpredictable conditions of Madagascar's environments.     

Special relationships instead of female dominance for redfronted lemurs,Eulemur fulvus rufus

Most lemurs yet studied in detail exhibit some mode of adult female social dominance over males. The known exception, a brown lemur subspecies known as rufous or redfronted lemurs (Eulemur fulvus rufus), forms multimale–multifemale social groups within which unambiguous dominance relations are not observed among adults. Resting groups of redfronted lemurs consistently include huddling adult male–female pairs whose males selectively scentmark and rub their heads in the scentmarks of their female huddling partners. Quantitative observations confirmed that some of these male–female pairs maintain special relationships satisfying all criteria originally developed in research on cercopithecine monkeys. Observations before, during, and after mating season, intergroup encounters, male transfers, and changes in male–female affiliations illuminated developmental and functional aspects of male–female partnerships. Each adult female in two semi-free-ranging study groups shared high rates of association, grooming, and agonistic support and low rates of agonistic interaction with one unrelated or distantly related adult male partner. Such affinity characterized small proportions of adult male–female relationships. Several males directed not only support but also aggression toward adult females with whom they sought to affiliate. All bonded males sought to copulate with their partners, and some appeared to ignore estrus in nonpartners. All females accepted copulation attempts from partners and some seemed to prefer their partners as mates. Partial synchronization of brief estrus periods together with concealed ovulation appeared to minimize chances for polygynous mating. Results support the view that the male–female pair is the fundamental social unit of E. fulvus and suggest that female partnership with individual males obviates dominance behavior, including female dominance, in this lemurid primate. Am. J. Primatol. 43:239–258, 1997. © 1997 Wiley-Liss, Inc.     

Reproductive Schedules of Female <Emphasis Type="Italic">Microcebus rufus</Emphasis> at Ranomafana National Park,Madagascar

I examined the reproductive status of female brown mouse lemurs (Microcebus rufus) from October 2005 to early January, 2006 at Ranomafana National Park, an eastern rain forest in Madagascar. I employed intensive capture/mark/recapture techniques to track individual changes in vaginal morphology and body mass and collected vaginal smears for individuals with open vaginas. I observed moderate estrous synchrony (vaginal openings between October 11 and November 18), with clusters of females showing strong estrous synchrony (6 of 15 on or around October 15, and 3 of 15 on or around October 25). My findings weakly support the proximity hypothesis—that closer females will enter estrus simultaneously—and offer virtually no support for the notion that body mass influences the timing of estrus in brown mouse lemurs. Females gave birth during the second and third weeks of December. Two females showing signs of abortion or perinatal death of offspring also showed renewed vaginal swelling in late December, suggesting that some form of polyestry, i.e., as reproductive compensation for infant loss, exists at Ranomafana. I discuss the implications of the data, in conjunction with other evidence of polyestry in wild mouse lemurs, in light of data on patterns of seasonality at Ranomafana and other sites. More data are needed to determine the frequency and pattern of polyestry in Microcebus rufus.     

Use of Vocal Fingerprinting for Specific Discrimination of Gray (Microcebus murinus) and Rufous Mouse Lemurs (Microcebus rufus)

Advertisement calls are often important noninvasive tools for discriminating cryptic species and for assessing specific diversity and speciation patterns in nature. We investigated the contribution of these calls to uncover specific diversity in nocturnal Malagasy lemurs. We compared sexual advertisement and predator advertisement calls of two mouse lemur species, western gray and eastern rufous mouse lemurs (Microcebus murinus and M. rufus, respectively) living in two contrasting habitats (dry deciduous vs. rain forest), and analyzed them statistically. Both species emitted several highly variable whistle calls in the context of predator-avoidance. Intrapopulation variation was high and overlapped interspecific variation. Sexual advertisement calls, given in the mating context, displayed a totally distinct, species-specific acoustic structure. Whereas gray mouse lemurs produced rapidly multifrequency modulated, long trill calls, rufous mouse lemurs gave slowly frequency-modulated short chirp calls. Our results suggest specific status for gray and rufous mouse lemurs and indicate the importance of predation and social needs in shaping vocal communication.     

Adult Male Scent-Marking in Lemur catta and Eulemur fulvus rufus

Scent-marking and olfactory communication are used extensively by prosimians and can provide spatial and temporal records of group movement and behavior. We compare rates of male scent-marking in relation to reproductive seasons, male dominance rank, and habitat use in two related prosimians: Lemur catta and Eulemur fulvus rufus. We collected scent-marking data on adult male Lemur catta at Beza-Mahafaly Reserve (dry forest), and on Eulemur fulvus rufus at Ranomafana National Park (rainforest), Madagascar. In Lemur, rates of overall scent-marking differed significantly by reproductive season, with higher rates occurring in mating and lactation/migration periods, whereas in Eulemur, reproductive season did not appear to affect scent-marking rates. Dominance rank of male Lemur catta did not affect rates of scent-marking. Among male Eulemur fulvus, dominance relations were not apparent; however, 2 of the 5 focal males scent-marked somewhat more frequently during the mating season and also experienced greater mating success. In Lemur catta, higher rates of scent-marking in the mating season may relate to indirect reproductive competition during a period of high aggression, while such mating competition was not as marked in Eulemur fulvus. Furthermore, higher rates of marking in resident male Lemur catta during male migration may correlate with vigilance toward immigrating males. Greater overall scent-marking rates in ring-tailed lemurs may relate to extensive intergroup home range overlap and no area of exclusive use, whereas the red-fronted lemur groups tended to forage in areas of their home range where little-to-no intergroup overlap occurred.     

Modeling problems in conservation genetics using captive Drosophila populations: Rapid genetic adaptation to captivity

Long-term captive breeding programs for endangered species generally aim to preserve the option of release back into the wild. However, the success of re-release programs will be jeopardized if there is significant genetic adaptation to the captive environment. Since it is difficult to study this problem in rare and endangered species, a convenient laboratory animal model is required. The reproductive fitness of a large population of Drosophila melanogaster maintained in captivity for 12 months was compared with that of a recently caught wild population from the same locality. The competitive index measure of reproductive fitness for the captive population was twice that of the recently caught wild population, the difference being highly significant. Natural selection over approximately eight generations in captivity has caused rapid genetic adaptation. Captive breeding strategies for endangered species should minimize adaptation to captivity in populations destined for reintroduction into the wild. A framework for predicting the impact of factors on the rate of genetic adaptation to captivity is suggested. Equalization of family sizes is predicted to approximately halve the rate of genetic adaptation. Introduction of genes from the wild, increasing the generation interval, using captive environments close to those in the wild and achieving low mortality rates are all expected to slow genetic adaptation to captivity. Many of these procedures are already recommended for other reasons. © 1992 Wiley-Liss, Inc.     

Husbandry,overwinter care,and reproduction of captive striped skunks (Mephitis mephitis)

The striped skunk (Mephitis mephitis) is the focus of research interest for a variety of reasons, including its roles as a rabies reservoir, urban pest, predator of bird eggs, and parasite host. Some research programmes may require husbandry and breeding of captive animals, and because skunks are inactive in the winter in northern environments, special methods are needed to maintain the animals over winter. We report on the establishment of a colony of striped skunks kept in captivity in the northern part of their range. Our goals were to develop simple and effective methods to keep skunks in captivity over winter, and successfully breed skunks in a manner that resembles conditions in the wild. In the spring of 2002, three wild‐caught, pregnant females gave birth in captivity (mean litter size=7). During the first year, 11 of 12 females kept in captivity over winter reproduced successfully in the spring of 2003, with a mean litter size of 5.5 (range=4–8, n=11). In the summer of 2003, 91 of 93 juveniles (97.9%) survived >60 days past weaning. Our high survival and reproduction rates testify to the success of this program, and provide insights into the husbandry of a species that is inactive during winter. Zoo Biol 24:83–91, 2005. © 2005 Wiley‐Liss, Inc.     

Mating system of Microcebus murinus

Microcebus murinus, a small nocturnal lemur from Madagascar, has retained features of ancient primates. Based on these ancestral traits, its social organization has often been used as a model for early primate social systems. In captivity it breeds polygynously, i.e., one male mates with several females, while females usually copulate only with the dominant male. The present project tested whether or not sexual size dimorphism, spatial distribution, and relative testis size of M. murinus correspond with predictions of the sexual selection theory concerning polygynous mating systems. The study was combined with a mark‐recapture study and radio tracking of 12 animals in 1993 in a dry deciduous forest of western Madagascar at the end of the dry season. Large overlapping home ranges in males, lack of sexual size dimorphism, and relatively large testes suggest a multi‐male mating system, i.e., one that is promiscuous rather than polygynous. Am. J. Primatol. 48:127–133, 1999. © 1999 Wiley‐Liss, Inc.     

Ecological Correlates to Lemur Community Structure in Southeast Madagascar

The Fandriana-Marolambo forest corridor is one of the largest (ca. 250,000 ha) and least explored tracts of unprotected forest in southeast Madagascar. Although published range maps show continuous distributions for many lemurs throughout the region, there are few data on lemur community structure in the corridor. We aimed to determine lemur community structure, with its ecological correlates (altitude, agriculture, selective logging, and hunting), in the Fandriana-Marolambo forest corridor. We surveyed 7 sites and sighted 4 nocturnal taxa (Avahi laniger, Cheirogaleus major, Lepilemur mustelinus, and Microcebus rufus) and 6 diurnal taxa (Eulemur rubriventer, E. fulvus rufus, E. f. fulvus, Propithecus diadema edwardsi, Hapalemur griseus griseus, and Varecia variegata variegata). Composition of the lemur community was broadly similar to that of nearby protected areas (Ranomafana and Mantadia National Parks). However, we sighted no Hapalemur aureus, H. simus, or Indri indri, and observed Propithecus diadema edwardsi and Varecia variegata variegata at only 1 site each. We sighted an apparent hybrid form of Eulemur fulvus fulvus and E. f. rufus that may represent a new hybrid zone for lemurs. After testing for spatial autocorrelation, lemur diversity correlates negatively with altitude and agricultural intensity. Though the Government of Madagascar is assessing the corridor as a new national park, we suggest conservation plans for local lemurs are complicated by population isolation and lack of data on minimum viable size of the proposed protected area.     

Paternity analyses in wild‐caught and laboratory‐reared Caribbean cricket females reveal the influence of mating environment on post‐copulatory sexual selection

Polyandry is ubiquitous in insects and provides the conditions necessary for male‐ and female‐driven forms of post‐copulatory sexual selection to arise. Populations of Amphiacusta sanctaecrucis exhibit significant divergence in portions of the male genitalia that are inserted directly into the female reproductive tract, suggesting that males may exercise some post‐copulatory control over fertilization success. We examine the potential for male–male and male–female post‐copulatory interactions to influence paternity in wild‐caught females of A. sanctaecrucis and contrast our findings with those obtained from females reared in a high‐density laboratory environment. We find that female A. sanctaecrucis exercise control by mating multiple times (females mount males), but that male–male post‐copulatory interactions may influence paternity success. Moreover, post‐copulatory interactions that affect reproductive success of males are not independent of mating environment: clutches of wild‐caught females exhibit higher sire diversity and lower paternity skew than clutches of laboratory‐reared females. There was no strong evidence for last male precedence in either case. Most attempts at disentangling the contributions of male–male and male–female interactions towards post‐copulatory sexual selection have been undertaken in a laboratory setting and may not capture the full context in which they take place – such as the relationship between premating and post‐mating interactions. Our results reinforce the importance of designing studies that can capture the multifaceted nature of sexual selection for elucidating the role of post‐copulatory sexual selection in driving the evolution of male and female reproductive traits, especially when different components (e.g. precopulatory and post‐copulatory interactions) do not exert independent effects on reproductive outcomes.     

Life in Unpredictable Environments: First Investigation of the Natural History of Microcebus griseorufus

The dry spiny forest of southern Madagascar is a highly unpredictable environment in terms of the amount and distribution of rainfall. The region is also subject to marked El Niño oscillations. One of the inhabitants of the region is Microcebus griseorufus (Kollman, 1910), the reddish-grey mouse lemur. During the 4 yr of the study, the focal population underwent marked fluctuations in size and exhibited a relatively long reproductive season: September–May. Subjects used daily torpor and expressed opportunistic seasonal fattening when food availability was high. They fed mainly on gum, especially during periods of drought. The estimated sex-ratio of the population is 54% female. Young males dispersed. Females and less frequently, males, associated in same-sex pairs that sometimes joined to form larger sleeping groups. I observed both erratic and resident males, the latter sometimes associated with females in sleeping groups. Mating occurred from September to January and involved mate-guarding. Individual female home ranges (N?=?14) overlapped with, on average, 2.8?±?0.3 male home ranges (range 2–5), whereas individual male home ranges (N?=?12) overlapped with 4.7?±?0.4 female home ranges (range 2–7). Female estrus was not synchronized, even within the female pairs, allowing alloparental care. Gestation lasted 52 d in 1 female, and litter size could be as high as 3; 20 reproductive females out of 37 adult females raised only 1 or 2 young per year.     

Effects of Transect Selection and Seasonality on Lemur Density Estimates in Southeastern Madagascar

I investigated how transect type (trails vs. cut transects) and seasonality influenced density estimates for 5 lemur taxa (Avahi laniger, Cheirogaleus major, Eulemur rubriventer, Hapalemur griseus griseus, and Microcebus rufus) in the Vohibola III Classified Forest in SE Madagascar. I surveyed tree height and diameter and lemur populations from June 1 to December 28, 2004 along 2 1250-m trails local people used and 2 1250-m transects cut parallel to the trails in primary rain forest. Despite dendrometric variations within and between trails and transects, only density estimates of Hapalemur griseus griseus differed significantly by transect type. The spatial variation may be a result of removal by local people of giant bamboo, which is the main food for Hapalemur griseus griseus, along trails. Conversely, seasonality influenced density estimates for Cheirogaleus major, Eulemur rubriventer, Hapalemur griseus griseus, and Microcebus rufus. The temporal variations may be related to seasonal torpor for Cheirogaleus major and increased detection probabilities during periods of fruit exploitation for Eulemur rubriventer, Microcebus rufus, and Hapalemur griseus griseus. Transect type and seasonality did not affect density estimates for Avahi laniger, which may be related to the highly folivorous and low-energy diet of the nocturnal lemur. Researchers surveying lemurs along line transects should be aware that transect selection may influence density estimates for Hapalemur griseus griseus and that seasonality may influence density estimates for Cheirogaleus major, Eulemur rubriventer, Hapalemur griseus griseus, and Microcebus rufus.     

Seasonal changes in general activity, body mass and reproduction of two small nocturnal primates: a comparison of the golden brown mouse lemur ( Microcebus ravelobensis) in Northwestern Madagascar and the brown mouse lemur ( Microcebus rufus) in Eastern Madagascar

To investigate for the first time the relationship between contrasting patterns of seasonal changes of the environment and activity, body mass and reproduction for small nocturnal primates in nature, we compared a population of golden brown mouse lemur (Microcebus ravelobensis) in a dry deciduous forest of northwestern Madagascar and of the brown mouse lemur (Microcebus rufus) in an evergreen rain forest of eastern Madagascar. Both species live under similar photoperiodic conditions. Golden brown mouse lemurs (GBML) were active during the whole period (May to December) irrespective of changing environmental conditions. In contrast, a part of the population of brown mouse lemurs (BML) showed prolonged seasonal torpor, related to body mass during periods of short day length and low ambient temperatures. Differences between species might be due to differences in ambient temperature and food supply. Body weight and tail thickness (adipose tissue reserve) did not show prominent differences between short and long photoperiods in GBML, whereas both differ significantly in BML, suggesting species-specific differences in the photoperiodically driven control of metabolism. Both species showed a seasonal reproduction. The rate of growth and size of the testes were similar and preceded estrous onset in both species suggesting a photoperiodic control of reproduction in males. The estrous onset in females occurred earlier in GBML than in BML. Estrous females were observed over at least 4 months in the former, but in only 1 month in the latter species. Intraspecific variation of estrous onset in GBML may be explained by body mass. Interspecific variation of female reproduction indicates species-specific differences in the control of reproduction. Thus, environmentally related differences in annual rhythms between closely related small nocturnal lemurs emerged that allow them to cope with contrasting patterns of seasonal changes in their habitats.     

Individual Facial Coloration in Male <Emphasis Type="Italic">Eulemur fulvus rufus</Emphasis>: A Condition-dependent Ornament?

Researchers studying individual variation in conspicuous skin coloration in primates have suggested that color indicates male quality. Although primate fur color can also be flamboyant, the potential condition dependence and thus signaling function of fur remains poorly studied. We studied sources of variation in sexually dichromatic facial hair coloration in red-fronted lemurs (Eulemur fulvus rufus). We collected data on 13 adult males in Kirindy Forest, Madagascar, during two study periods in 2006 and 2007, to determine whether variation in facial hair coloration correlates with male age, rank, androgen status, and reproductive success. We quantified facial hair coloration via standardized digital photographs of each male, assessed androgen status using fecal hormone measurements, and obtained data on reproductive success through genetic paternity analyses. Male facial hair coloration showed high individual variation, and baseline coloration was related to individual androgen status but not to any other parameter tested. Color did not reflect rapid androgen changes during the mating season. However, pronounced long-term changes in androgen levels between years were accompanied by changes in facial hair coloration. Our data suggest that facial hair coloration in red-fronted lemur males is under proximate control of androgens and may provide some information about male quality, but it does not correlate with dominance rank or male reproductive success.     

Endocrine Correlates of Reproductive Status in Breeding and Nonbreeding Wild Female Moustached Tamarins

In callitrichid primates, reproduction is usually restricted to a single female per group. Reproductive rate is high and the occurrence of a postpartum estrus can lead to simultaneous lactation and pregnancy. In contrast, nonreproductive females often show ovarian inactivity. However, most studies on callitrichid reproductive physiology have been conducted in captivity, where conditions differ considerably from those in the wild, so that reproductive conditions may be strongly modified. Using fecal estrogen and progestogen measurements to monitor female reproductive status in 2 groups of wild moustached tamarins (Saguinus mystax), we examined 1) whether reproductive females in free-ranging groups also show postpartum estrus and 2) whether nonreproductive females demonstrate signs of ovarian activity. In both reproductive females, clear changes in the excretion pattern of progestogen and estrogen metabolites over time in combination with information on parturition dates allowed us to differentiate between pregnancy, a period of postpartum ovarian inactivity lasting for 54 and 64–82 days, and a period of ovarian activity before conception. Nonreproductive females demonstrated temporal fluctuations in hormone concentrations and absolute hormone levels that were similar to ones in the breeding females during the phase of ovarian activity. The results suggest that, in contrast to most captive female tamarins, reproductive females in wild groups of moustached tamarins do not have a postpartum estrus and that nonreproductive females show ovarian activity despite the presence of a breeding female. We therefore conclude that findings from captivity should be only carefully compared to the situation in the wild.     

Lice and ticks of the eastern rufous mouse lemur, Microcebus rufus, with descriptions of the male and third instar nymph of Lemurpediculus verruculosus (Phthiraptera: Anoplura)

Sucking lice and ticks were collected from live-trapped eastern rufous mouse lemurs, Microcebus rufus Geoffroy, in and around the periphery of Ranomafana National Park, southeastern Madagascar, from 2007 to 2009. Samples of 53 sucking lice (Insecta: Phthiraptera: Anoplura) and 28 hard ticks (Acari: Ixodidae) were collected from 36 lemur captures representing 26 different host individuals. All of the lice were Lemurpediculus verruculosus (Ward) (6 males, 46 females, 1 third instar nymph). Only the holotype female was known previously for this louse and the host was stated to be a "mouse lemur." Therefore, we describe the male and third instar nymph of L. verruculosus and confirm M. rufus as a host (possibly the only host) of this louse. All of the ticks were nymphs and consisted of 16 Haemaphysalis lemuris Hoogstraal, 11 Haemaphysalis sp., and 1 Ixodes sp. The last 2 ticks listed did not morphologically match any of the Madagascar Haemaphysalis or Ixodes ticks for which nymphal stages have been described.     

Clinical chemistry and hematology values in a Caribbean population of African green monkeys

Background Hematology and clinical chemistry (HCC) reference values are critical in veterinary practice and in vivo pre‐clinical research, enabling detection of health abnormalities, response to therapeutic intervention or adverse toxicological effects, as well as monitoring of clinical management. Methods In this report, reference ranges for 46 HCC parameters were characterized in 331 wild‐caught and colony‐bred African green monkeys. Effects of sex, weight and duration of captivity were determined by one‐way analysis of variance. Results Significant sex differences were observed for several HCC parameters. Significant differences were also observed for select HCC variables between newly caught animals and those held in captivity for 1–12 months or longer. Conclusions Comparison of this data with other non‐human primate species and humans highlights similarities and disparities between species. Potential causes of interpopulation variability and relevance to the use of the African green monkey as a non‐human primate model are discussed.     

Selected aspects of Lemur variegatus reproductive biology

Results from data collected during the 1978–1979 breeding season on the reproduction of Lemur variegatus at the San Diego Zoo provide information which generally supports previously published reports on this species. Comparison of selected results from these data to a larger data base of which they are a part makes it possible to resolve some of the discrepancies between reports. Certain aspects of the reproductive biology of this species may then be generally characterized with confidence: The onset of seasonal breeding as evidenced by estrous behavior begins as early as mid-December in the northern hemisphere and may continue through March; genital changes associated with estrus in females last 9.85 ± 1.67 days (± SD); female receptivity occurs 7.0 ± 1.53 days after the onset of these genital changes and lasts 12-24 hours, during which breeding occurs; gestation averages 99.47 ± 4.19 days; the peak birth season is April–May; litters normally contain two to three offspring, with full-term neonates weighing an average of 104.63 ± 19.10 grams. In addition, L variegatus appears to be highly resistant to the impact of captivity on both its reproductive physiology and behavior, as indicated by the 100% breeding success of the diversely reared and managed groups of study animals.