Welcome to the Wildlife Endocrinology Lab


I’m Jocelyn Bryant, the Endocrinology Lab Manager at Brookfield Zoo. I get to work with amazing animals and participate in incredible research projects. I have had the privilege of working with over 50 species from Brookfield Zoo as well as animals from other institutions.  Partnerships are an important part of the research process and have occurred since the lab opened in 2001.

In the lab, I monitor the hormonal activity in wildlife and incorporate anecdotal behavioral information provided by the keepers.  I am most interested in the indicators of positive and negative welfare.  Reproductive hormones such as progesterone and estrogen can tell us if an animal is cycling regularly, entering estrus, or may be pregnant.

Franny and her new calf Arnieta in 2007. Franny's fecal progestogen levels were monitored throughout her pregnancy to keep an eye on hormone concentration and to create a valuable pregnancy profile. The profile has been used as a reference in subsequent giraffe pregnancies.

I can also measure the glucocorticoid steroids cortisol and corticosterone, which may indicate acute and chronic stress.  Acute stress tends to be short-lived with a quick recovery time, and can actually be beneficial to an animal by increasing cognitive function.  On the other hand, chronic stress occurs on a more long term basis and may cause immune function suppression or lower reproductive success.  With an evidence-based approach to animal care and welfare, the Chicago Zoological Society – Brookfield Zoo ensures animals are not under chronic stress and have the right amount of stimulation in their lives.

An example of a short-term stress response in the African lion. This peak occurred during a vet exam, and hormone levels returned to normal shortly thereafter.

Most of the lab work is done using fecal samples as it’s easy to collect and non-invasive to the animal.  The hormone and its metabolites can easily be extracted from feces using an alcohol mixture.  It is also possible to use urine, saliva, and blood—other types of biological samples such as hair, feathers, and even reptile sheds are on the forefront of research as potential methods for measuring hormone levels.

An Endocrinology Lab volunteer preparing test tubes for fecal hormone extraction.

A majority of the research studies I am participating in are long-term and create extensive hormonal profiles.  I can use these profiles to monitor an animals’ hormonal patterns over time and determine if certain variables may be causing hormonal responses.  Since this technology is still relatively recent, there are still many research areas to pursue including: developing new assays to measure other hormones, measuring various components of the autonomic nervous system (ANS), and assessing aspects of immune function.  I’m also incorporating more innovative technology into the lab work such as high performance liquid chromatography (HPLC) in order to learn more about the particles in the hormone extracts. 

My overall goal is to increase knowledge on the health, welfare, and reproductive activity on as many species as possible.  This will help ensure the animals in our care are experiencing optimal welfare.

Stay tuned for more exciting research from our lab!
Jocelyn Bryant
Endocrinology Lab Manager

Posted: 7/12/2016 3:27:08 PM by Bryan Todd Oakley

CZS & Brookfield Zoo

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