What’s going on inside may explain what’s happening outside

By Dana Kobilinsky

A black bear wanders alongside a road in Yellowstone National Park. Conservation endocrinologists are starting to look at how factors such as ecotourism affects stress hormones in wildlife. ©Adam Fagen

Wildlife biologists often look outward at habitat and ecology to understand impacts on the species they study. A growing number of biologists are looking inward, though, to try to understand what an individual animal’s hormones can tell them about environmental factors affecting wildlife populations.

In a review published in the journal BioScience, scientists looked at how the emerging field of conservation endocrinology can be used to conserve species.

The field has been growing over the last 20 years, said Stephen McCormick, a senior scientist and research physiologist with the U.S. Geological Survey and the lead author of the review, and in that time, scientists have made some key advances in their understanding and in their techniques. Scientists can now measure hormones not just in blood but in scales, feathers, nails, hair, feces and urine, he said.

“The real crux of the thing is, we need to more and more take examples of individuals and make predictions for populations,” McCormick said. “A lot of work at zoos or universities is interested in individual welfare of an animal, but after we learned a great deal about what hormones mean to the animal itself, I think we can start moving away from the lab and out into the wild.”

Scientists have learned more about how stress hormones work in some species, McCormick said, allowing them to see how animals may respond to human disturbances. That could include activities such as ecotourism in which humans and wildlife may interact in close quarters.

“The classic way hormones work is they’re released from a gland and travel through the blood and bring about physiological responses,” he said. “Responses to the environment change and hormones coordinate a response throughout the body.”

Conservation endocrinologists hope to learn more about how the effects of climate change, including reduced precipitation and rising temperatures, may affect animals’ stress hormones, and how certain contaminants that act as endocrine disruptors may interfere with reproductive hormones.

University courses on conservation physiology and endocrinology are rare, McCormick said, but their numbers are growing.

“This is a field with increasing relevance to conservation issues,” he said. “We need to have people working together to know the natural history of the animals, we need good population ecologists and we need to have good endocrinologists working together to introduce hormones in the field to a broader audience.”

Dana KobilinskyDana Kobilinsky is a science writer at The Wildlife Society. Contact her at dkobilinsky@wildlife.org with any questions or comments about her article. You can follow her on Twitter at @DanaKobi.

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