Animal Welfare Research: Endocrinology

The Endocrinology Program was launched in 2001 to take advantage of an exciting area of animal welfare research that helps improve the well-being and reproductive success of species, both in zoos and in the wild.  Endocrinology is the study of hormones and their functions.  Hormones are released from various endocrine glands in the body such as reproductive hormones (e.g. estrogen, testosterone) from the gonads and “stress” hormones (e.g. cortisol, corticosterone) from the adrenal glands. Quite often, hormonal data can be used in conjunction with Animal Behavior for a more comprehensive approach.

Most commonly we measure hormones in fecal samples, but they can also be measured in blood, serum, urine, and saliva. Fecal samples are ideal because sample collection is non-invasive and samples are easy to collect. Our lab runs EIA’s (enzyme-immuno assays) on the samples to determine hormone concentrations.

Among its successes, the CZS’s Endocrinology Program has:

  • Improved reproductive success for a wide array of animals including okapi, gorilla, fishing cat, aardvark, and Amur tiger.
  • Determined the reproductive patterns and/or developed pregnancy profiles for species such as fennec fox, gibbon, red river hog, wombat and black rhino.
  • Conducted multi-zoo research studies to assess the reproductive patterns of Amur tigers and determine the impacts of environmental factors on the “stress” hormones of clouded leopards and make improvements to exhibits.
  • Examined the adrenal (“stress”) hormones of African elephants, clouded leopards, gorillas, okapi, orangutans and red river hogs to assist animal care staff and inform management decisions.


A Leader in the Field

The Endocrinology Program positions CZS on the leading edge of scientific innovation. The Endocrine Lab is one of only a handful of labs worldwide that has validated hormone assays on over 50 species. We also are on the forefront of focusing on both positive and negative indicators of animal welfare, validating new assays, monitoring new species, and identifying various types of biological samples (e.g. feather, hair, and eggs) to measure hormone levels.  We currently are one of the only labs in the country to receive samples from other zoological institutions and to provide consultation and training services. Click here for more information about our current list of services provided by the Endocrinology Service Lab. Or contact our Endocrinology Lab Manager at 

Animal Welfare Research