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Critter Chemistry

April 9, 2001

Panda Scents

Perennial Zoo Favorites Use Complex Molecular Mix to Communicate

Elizabeth Wilson


HANGIN' OUT Not yet 18 months old, San Diego's Hua Mei is a crowd pleaser.

At the San Diego Zoo, preternaturally cute and fuzzy giant pandas are not just crowd pleasers. They're also ambling, tumbling chemistry labs. Pandas produce a palette of scent molecules and use their tails as paintbrushes to spread olfactory graffiti on bushes, trees, and rocks.

In fact, scent is the panda's primary form of communication, Lee R. Hagey, manager of the analytical chemistry division of the San Diego Zoo's Center for Reproduction of Endangered Species, said at the ACS national meeting in San Diego last week. The odors can say anything from "I can reproduce!" to "Back off, bub, this is my territory."

Hagey and his colleagues are using analytical techniques such as gas chromatography and mass spectrometry to decode the panda's scent-based "message board." The chemicals found in scent markers left by males, the researchers have discovered, are almost all breakdown products of amino acids. The male pandas secrete precursor molecules that are subsequently decomposed by bacteria in the scent glands to produce the chemical fingerprint.

Female pandas, on the other hand, don't use their scent glands to communicate. Their scent marker is urine, and it is used primarily to advertise reproductive status. The urine marker's chemical makeup is far more complex, Hagey said. It's also far more volatile, and so more short-lived.

The locale of the panda's scent isn't limited to its nether regions. In fact, the animals are scented from ears to tail and touch themselves in very deliberate ways to distribute odors. For example, they rub their ears with urine, then sit upright to disseminate the odor through the breeze.

Although pandas also rub their eyes, urine scents curiously never end up in that spot. How do they do it Pandas rub their ears with the front of their paws, and their eyes with the back, Hagey said.

Chemical & Engineering News
ISSN 0009-2347
Copyright © 2010 American Chemical Society