Panda footprints offer identity clues

Footprints left by giant pandas in the snow can be used by researchers to determine their gender, according to Zhang Hemin, deputy director of the China Conservation and Research Center for the Giant Panda in Sichuan province.

The technology used to determine the gender of wild pandas from footprints in the snow will be especially helpful for monitoring captive pandas that have been reintroduced to the wild, Zhang said on Friday while commenting on research conducted by Duke University in the United States.

The research was done in cooperation with Zhang's center, which has 270 captive pandas - the largest number of captive pandas in the world.

Researchers collected images from captive pandas at the center from March 2014 to April 2016, mostly in a sand preparation, since snowfall was infrequent at the lower altitudes where captive pandas were held.

However, they also collected footprints in the snow from captive pandas when enough snow had accumulated in the enclosures at a higher altitude.

Researchers used an interactive software tool called Footprint Identification Technique to "read" and analyze digital images of footprints that are submitted electronically to a global database for matching, according to the website ScienceDaily.

Forty-one captive pandas from Zhang's center were part of the research. FIT correctly identified their gender more than 90 percent of the time, according to a recent article in Biological Conservation, a leading international journal. Zhang was a co-author of the article.

The technique can also accurately identify individual animals more than 90 percent of the time, according to the website of Duke University's Nicholas School of the Environment.

Male and female pandas differ in weight and gait, which helps researchers use footprints to determine a panda's gender. Adult male pandas are from 10 to 20 percent larger than adult females, so their footprints tend to be bigger, Zhang said.

Thanks to FIT, researchers can now find pandas reintroduced into the wild in the Liziping Nature Reserve through footprints in the snow, said Zhang.

Binbin Li from Duke Kunshan University contributed to this story.

huangzhiling@chinadaily.com.cn