oregon zoo Endocrinology Lab

Candace Scarlata prepares samples for analysis in a new lab at the Oregon Zoo where hormones will be monitored to assess animals' state of well-being.

(Michael Durha/Oregon Zoo)

Animals kept in captivity in zoos and other facilities can't directly tell their keepers how they're feeling, so caretakers often have to rely on behavioral observations and other assessments.

Along those lines, the Oregon Zoo has equipped and staffed a new endocrinology lab to help establish a set of measures for assessing how the animals in their care are doing.

With a grant from the Oregon Zoo Foundation, the lab will work on developing more advanced means of monitoring hormone levels, which can provide one measure of an animals' well-being.

Key hormones for monitoring captive animals are the so-called stress hormones, or glucocorticoids. Tracking such hormones over time and across changes in an animal's environment can give keepers an idea of how that animal is reacting to its captive habitat, fellow animals and enrichment activities.

In some cases, a little stress is not necessarily a bad thing, zoo officials said. That includes instances such as when new animals are introduced into exhibits or a prospective mate is presented, offering stimulation and challenges that mimic experiences animals might have in the wild and allowing them to engage in natural, healthy behaviors.

"We need to interpret our data carefully and use multiple measures to understand when good stimulating stressors become negative stressors that may result in distress or chronic stress," Nadja Wielebnowki, the zoo's conservation and research manager, said in a statement.

Monitoring animals' hormone levels is not entirely new at the zoo, where staff have kept tabs on testosterone and progesterone in its elephants for more than 25 years in relation to breeding, gestation and musth cycles.

The new lab will begin tracking glucocorticoids and other hormones in the zoo's animals soon. Staff plan to couple the hormone data with other existing measures of physical health and behavioral observations to keep tabs on the zoo's captive critters.

-- Susannah L. Bodman, sbodman@oregonian.com, www.facebook.com/Sciwhat.Science, Twitter: @Sciwhat