Injections to pregnant mice produce prenatal stress that affects aggressive behavior in their adult male offspring

Maternal stress could reprogram the developing fetal nervous system. A common target of maternal glucocorticoids is fetal neuro-endocrine axis. In the present study, pregnant mice were exposed to stress by injection and their male offspring were tested for sexual and aggressive behaviors in adult life. Three groups of pregnant mice were exposed to stress by […]

Lizards perceived abiotic and biotic stressors independently when competing for shade in terrestrial mesocosms

Hormones such as glucocorticoids and androgens enable animals to respond adaptively to environmental stressors. For this reason, circulating glucocorticoids became a popular biomarker for estimating the quality of an environment, and circulating androgens are frequently used to indicate social dominance. Here, we show that access to thermal resources influence the hormones and behavior of male […]

Investigation of the efficacy of the GnRH agonist deslorelin in mitigating intraspecific aggression in captive male Amur leopards (Panthera pardus orientalis)

Housing bachelor groups is a necessary aspect of the care and husbandry of non-breeding individuals in zoological collections. Intraspecific aggressive behaviors may occur in this setting despite management strategies designed to mitigate these behaviors. Androgens (including testosterone) are associated with aggression in male species and interventional techniques to alter the animals’ physiology to modify aggressive […]

Hormonal correlations at transition from reproduction to molting in an annual life cycle of Humboldt penguins (Spheniscus humboldti)

To understand the hormonal mechanism behind a unique strategy of breeding and molting in Humboldt penguins, six pairs of captive Humboldt penguins kept in an outdoor open display pen were observed and blood collected weekly for a year. They all molted between the middle of June and the middle of August within 10 days except […]

Serum testosterone in captive male rhinoceros: Effects of season, age, stress, and sociosexual environment

All rhinoceros species are in some degree of endangerment. Understanding the reproductive physiology of rhinoceros species will help in management decisions with both free-ranging and captive populations. In mammalian species studied, testosterone plays a key role in spermatogenesis and libido. Testosterone concentrations, depending on the species, may vary according to age, season, social status, stress […]

Housing and welfare in laboratory rats: effects of cage stocking density and behavioural predictors of welfare

Using male and female Alderley Park (Wistar-derived) rats housed in single-sex groups in standard laboratory cages, we looked at the effect of group size (one, three, five or eight) on competitive behaviour and time budgeting (initial and longer term), changes in their serum testosterone (males), corticosterone and antibody concentrations, and organ pathology at age 16 […]

A safer method for studying hormone metabolism in an Asian elephant (Elephas maximus): accelerator mass spectrometry

Abstract Noninvasive hormone assays provide a way to determine an animal’s health or reproductive status without the need for physical or chemical restraint, both of which create unnecessary stress for the animal, and can potentially alter the hormones being measured. Because hormone metabolism is highly species-specific, each assay must be validated for use in the […]

Development of a field-friendly technique for fecal steroid extraction and storage using the African wild dog (Lycaon pictus)

Abstract 10.1002/zoo.20248.abs Hormonal analysis provides information about wildlife populations, but is difficult to conduct in the field. Our goal was to develop a rapid and effective field method for fecal steroid analysis by comparing: (1) three extraction methods (laboratory (LAB), homogenize (HO) and handshake (HS)) and (2) two storage methods (solid-phase extraction (SPE) tubes vs. […]

A simplified method for extracting androgens from avian egg yolks

Abstract 10.1002/zoo.20221.abs Female birds deposit significant amounts of steroid hormones into the yolks of their eggs. Studies have demonstrated that these hormones, particularly androgens, affect nestling growth and development. In order to measure androgen concentrations in avian egg yolks, most authors follow the extraction methods outlined by Schwabl (1993. Proc. Nat. Acad. Sci. USA 90:11446–11450). […]

Reproductive and thyroid hormone profiles in captive Western fence lizards (Sceloporus occidentalis) after a period of brumation

Abstract 10.1002/zoo.20159.abs Seasonal fluctuation in serum concentrations of sex steroid (testosterone [T] and 17β-estradiol [E2]) and thyroid (triiodothyronine [T3] and thyroxine [T4]) hormones was determined in captive Western fence lizards (Sceloporus occidentalis). Samples were collected from male and female breeding pairs weekly for a 4-month period after their emergence from artificial brumation. Circulating levels of […]