Birth and simultaneous rearing of two litters in a pack of captive African wild dogs (Lycaon pictus)

Abstract 10.1002/zoo.20111.abs Two female African wild dogs (Lycaon pictus) in a pack of 10 animals at the Bronx Zoo gave birth to litters of nine and seven pups within a 2-day period. Two pups from the litter of seven died before they were 2 weeks old, but the other 14 survived past weaning. Litter size, […]

Social suppression of female reproductive maturation and infanticidal behavior in cooperatively breeding Mongolian gerbils

In several cooperatively breeding species, reproductively suppressed, nonbreeding females are attracted to infants and routinely provide alloparental care, while breeding females may attack or kill other females’ infants. The mechanisms underlying the transition from alloparental to infanticidal behavior are unknown. In this study, we tested the hypothesis that this transition is associated with cessation of […]

The physiology of cooperative breeding in a rare social canid; sex, suppression and pseudopregnancy in female Ethiopian wolves

Ethiopian wolves, Canis simensis, differ from other cooperatively breeding canids in that they combine intense sociality with solitary foraging, making them a suitable species in which to study the physiology of cooperative breeding. The reproductive physiology of twenty wild female Ethiopian wolves (eleven dominant and nine subordinate) in Ethiopia’s Bale Mountains National Park was studied […]

Intrasexual competition and female dominance in a singular breeding mammal, the Alpine marmot

Although long neglected, female competition is widespread and may have stronger evolutionary consequences than previously thought. In singular breeders, reproductive success is conditional on social status, and intrasexual competition for the dominant position can be particularly severe in females. Because the ability of females to secure the dominant position may strongly influence their fitness, a […]

Social influences on the estrous cycle of the captive sun bear (Helarctos Malayanus)

We examined the potential influences of existing social housing arrangements on captive sun bear female reproductive cycling. Three social conditions were studied: 1.2, 1.1, and 0.2. Fecal hormone metabolites of total estrogens, progestins and glucocorticoids were compared between the three social conditions and were analyzed along with vaginal cytology data in individuals that experienced a […]

Fitness and hormonal correlates of social and ecological stressors of female yellow-bellied marmots

The effects of social and ecological stressors on female reproductive success vary among species and, in mammals, previous reviews have identified no clear patterns. However, few studies have simultaneously examined the relation between social rank and stressors and the relationships among rank, stressors and reproductive success. We used a long-term data set to study free-living […]

Hormonal correlates of development and natal dispersal in wild female owl monkeys (Aotus azarae) of Argentina

Pair-living and socially monogamous primates typically do not reproduce before dispersing. It is currently unclear whether this reproductive suppression is due to endocrine or behavioral mechanisms. Cooperatively breeding taxa, like callitrichids, may forego reproduction in natal groups because they reap inclusive fitness benefits and/or they are avoiding inbreeding. However, neither of these benefits of delayed […]