Fecal steroid analysis of female giraffe (Giraffa camelopardalis) reproductive condition and the impact of endocrine status on daily time budgets
Gestation and lactation can impose substantial energetic costs on female mammals. We developed a non-invasive means to determine reproductive condition in female giraffe using fecal steroid analysis. Giraffe may be especially challenged during their reproductive cycle because of two characteristics: they are impregnated while lactating and they do not breed seasonally. We studied the social […]
Communal nesting is unrelated to burrow availability in the common warthog
Warthogs, Phacochoerus africanus, are an unusual ungulate. They are facultative cooperative breeders where females within the same population display both solitary and cooperative reproductive strategies. Warthogs require burrows for sleeping and rearing their young, yet they are unable to dig their own burrows and rely on aardvark excavations. Studies of warthogs have failed to show […]
Sex and helping: reproductive strategies of breeding male and female cotton-top tamarins, Saguinus oedipus
Female marmosets and tamarins typically give birth to twins, and appear to need considerable assistance from the male and from other group members if they are to rear the young successfully. To ensure that male help is available, females would be expected to increase the time they devote to the pair relationship shortly before birth. […]
Maternal Investment in Captive Giraffes
Sex-biased maternal investment involves differential allocation of resources to production and rearing of sons or daughters as a function of their anticipated reproductive output. We examined reproductive investment among captive giraffes (Giraffa camelopardalis) over a 21-year period to determine extent to which females invest differentially in offspring by sex. We found an unbiased sex ratio […]
Mink with Divergent Activity Levels have Divergent Reproductive Strategies
Stable individual differences in activity levels within populations have been linked to differences in reproductive rate or parental care in several species, including American mink (Neovison vison). Fur-farmed mink are good models for studying such effects because they yield large sample sizes and readily allow investigations into maternal behaviour, reproductive success, offspring performance and the […]
Fitness Consequences of Maternal Rearing Strategies in Warthogs: Influence of Group Size and Composition
Cooperatively breeding species are defined by the presence of individuals who help in rearing the offspring of others. This seemingly altruistic behaviour has been difficult to define and the help provided has not always resulted in a reproductive advantage to the recipient. We examine maternal rearing strategies in the common warthog, Phacochoerus africanus, a facultative, […]