Biorythms in Panda Pairs
(October 2002)

 This information was presented by David Powell, Ph.D. at the 4th International Symposium on the Behavior and
Physiology of Zoo and Wild Animals in Berlin, October 2002.

Circadian rhythms and activity patterns in a pair of captive giant pandas (Mei Xiang and Tian Tian)
(Ailuropoda melanoleuca)

Relatively little biological information is published about giant pandas despite their tremendous public appeal and over 25 years of research on captive and wild animals.

The basic activity patterns and 24-hour activity patterns of relatively few pandas have been studied and the only standardized nighttime (nocturnal) observations of captive giant pandas were conducted at the National Zoological Park on two animals in the 1970s.

The objectives in this study were to 1) characterize 24-hour activity patterns in the National Zoo's new pandas, Mei Xiang and Tian Tian, 2) compare their patterns and activities with those of the previous pair of pandas at the Zoo, Ling Ling and Hsing Hsing, and 3) identify seasonal changes in activity.

We collected data by doing 4-day, round-the-clock watches and one-week long night watches (4pm-7am) of the pandas twice per year, in addition to ongoing observations that take place during the day.

Night-time observations showed that the pandas tended to rest from 5 p.m. to about 9 or 10 p.m., and then became active for a couple of hours to feed before going back to sleep until a little before or after sunrise.

The timing of their nighttime activity period depended on the time of year. These patterns were similar to those of Ling Ling and Hsing Hsing. This pattern of activity is opposite to that found in wild pandas, which were more active from 5 p.m. to 10 p.m. and less active from 10 p.m. to 2 a.m.

Our round-the-clock observations showed us that Mei Xiang and Tian Tian are remarkably synchronous in their behavior, feeding, resting, and investigating their environment at about the same time as each other, day or night, whether they were together or separated. This was also true for Ling Ling and Hsing Hsing when they were young.

George Schaller, who studied giant pandas in the wild, found a high level of synchronicity in behavior in one pair of wild pandas but not in another. Most behaviors occurred at a more or less constant level throughout the year.

Feeding and Exploring declined in August, the hottest part of the summer, but returned to previous levels in September. Stereotypic behavior (paw sucking, pirouetting) in the male increased in May and remained high until September. Previous studies of wild pandas also found seasonal decreases in activity occurring in August and September with resumption of normal activity levels in October.

Powell, D.M., Tarou, L.R., & Kleiman, D.G. 2002. Circadian rhythms and activity patterns in a pair of captive giant pandas (Ailuropoda melanoleuca). Advances in Ethology 37, p. 66.

DAVID M. POWELL 1, LORAINE R. TAROU1, DEVRA G. KLEIMAN1, ZHANG HEMIN2, AND ZHANG GUIQUAN2

1Department of Conservation Biology, Smithsonian National Zoological Park, 3001 Connecticut Avenue N.W., Washington D.C. 20008, U.S.A., powelldm@nzp.si.edu, 2China Research and Conservation Center for the Giant Panda, Wolong Nature Reserve, Sichuan, P.R.C.

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