Determinants of Home Range Size for Polar Bears (Ursus maritimus)

The mean home range size of female polar bears (Ursus maritimus; 125 100 km2 ± 11 800; n = 93) is substantially larger than the predicted value (514 km2) for a terrestrial carnivore of similar weight. To understand this difference, we correlated home range size and sea ice characteristics. Home range size was related to […]

Age at sexual maturity of males and timing of the mating season of polar bears (Ursus maritimus) in Greenland

Age at sexual maturity among male polar bears (Ursus maritimus) and timing of the mating season were studied by microscopic and macroscopic analysis of the reproductive organs from 165 male and 92 female Greenland polar bears. Males became sexually mature in the spring following their fifth birthday. Testes sampled during the spring reached 95% of […]

The Importance of Interactions Among Nutrition, Seasonality and Socio-sexual Factors in the Development of Hormone-free Methods for Controlling Fertility

Around the world, consumers are demanding animal products that are produced to agreed standards for human health, environmental management and animal welfare. This has led to the development in Australia of the concept of ‘clean, green and ethical’ (CGE) animal production based on the manipulation of nutrition (‘focus feeding’) and the application of phenomena, such […]

Significance of color, calories, and climate to the visual ecology of catarrhines

Here we describe correlations among visual ecology and the physiochemical properties of fruits and leaves consumed by four species of catarrhine primate: Cercopithecus ascanius, Colobus guereza, Pan troglodytes, and Piliocolobus badius. Collectively, their diet was diverse, with each species relying on fruits and leaves to different extents. The mean chromaticity of both foods, as perceived […]

Characterization of basal seminal traits and reproductive endocrine profiles in North American river otters and Asian small-clawed otters

Abstract 10.1002/zoo.20206.abs In this study, fecal samples were collected from 24 North American river (NARO) and 17 Asian small-clawed otters (ASCO) for 6–36 months and semen collected seasonally from NARO males (n=4/season) via electroejaculation. Our main objectives were to: (1) characterize endocrine parameters by longitudinal monitoring of fecal hormone metabolites and (2) investigate semen collection […]

Reproductive patterns in pygmy lorises (Nycticebus pygmaeus): Behavioral and physiological correlates of gonadal activity

Abstract 10.1002/zoo.10072.abs The purpose of this study was to evaluate behavioral and physiological parameters of reproduction in a breeding colony of pygmy lorises. To this end, nine male and eight female adult pygmy lorises were kept under natural lighting conditions and monitored through five consecutive breeding seasons. Behavioral data were collected continuously throughout the year […]

Reproductive endocrine responses to photoperiod and exogenous gonadotropins in the pallas’ cat (Otocolobus manul)

Abstract Fecal samples were collected for 14–26 months from three male and six female Pallas’ cats (Otocolobus manul) to examine gonadal steroidogenic activity in response to changes in photoperiod and treatment with exogenous gonadotropins. Females exhibited a seasonal anestrus from May–December, excreting consistently low concentrations of fecal estrogens (overall mean, 50.2±8.5 ng/g). During the breeding […]

Status and reproductive potential of lion-tailed macaques in captivity

Abstract 10.1002/zoo.1430080503.abs Publication of a studbook for Macaca silenus in 1983 provides detailed demographic information on the captive North American population. These data indicate that females reach sexual maturity at about 4 years of age, whereas onset of reproduction for males occurs at age 5. One-third of all sexually mature females and 57% of sexually […]

Reproductive parameters of clouded leopards (Neofelis nebulosa)

Abstract 10.1002/zoo.1430080303.abs Reproductive data compiled from the International Clouded Leopard Studbook revealed that 75% of all litters were born to females between one and five years of age. Sixty-three percent of the males had sired litters by four years of age with reproduction declining after six years of age. Sixteen zoological institutions surveyed worldwide contributed […]

Puberty in female cavies (Cavia aperea) is affected by photoperiod and social conditions

In many environments, photoperiod is a reliable predictor of ecological conditions. Such predictability generally declines towards low latitudes as the yearly cycle becomes less marked. It has been claimed that photoperiodic effects are small in cavies and guinea pigs that reproduce throughout the year. We here investigated photoperiodic influences on the onset of puberty in […]