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Giant Panda
Behavior/Bamboo Preferences
Scientists at the Smithsonian’s National
Zoo work with colleagues at Chinese and other North
American zoos to tackle two of the great obstacles to
breeding giant pandas (Ailuropoda melanoleuca)—why
zoo pandas often show little interest in mating, and
why zoo male pandas are at times overly aggressive toward
prospective mates. After studying zoo pandas in China,
National Zoo scientists and their colleagues recommended
that enclosures for male pandas contain tall vegetation,
climbable trees, and areas set back from close public
viewing, as well as nearby scents—scat, or dung,
from other pandas. These considerations may reduce stress
and get the animals better acquainted with potential
mates. Such steps are taken at the National Zoo’s
giant panda enclosure. Meanwhile, Zoo scientists and
their colleagues also conducted the first-ever study
of zoo-panda preferences for different species of bamboo,
the giant grasses that constitute 99 percent of the
bears’ diet.
Foraging/Cognition
By keeping a careful eye on National Zoo pandas
Tian Tian and Mei Xiang, Zoo scientists, keepers, and
FONZ volunteers help to improve our understanding of
how giant pandas operate, both in zoos and in the wild.
Staff keep close tabs on which parts and types of bamboo
the pandas prefer, how they use their exhibit, including
their dens, trees, and playthings, and especially how
they interact with each other. For instance, male Tian
Tian employs all known scent-marking postures and female
Mei Xiang is using new behaviors since arriving at the
Zoo, including bleating and chirping during the breeding
season.
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MXPanda.jpg)
Zoo scientists also study how efficiently the Zoo’s pandas, along with those at Zoo Atlanta and the San Diego Zoo, forage for food within their enclosures. So far, it seems that these pandas primarily rely upon spatial, rather than olfactory or visual, cues to find food. Across consecutive trials, the pandas learned how to improve their foraging efficiency by avoiding locations often lacking food and frequenting more productive sites. This study has important implications for wild panda conservation because it suggests that once pandas find reliable food sources, they may not find new foraging sites easily.
Characterizing estrus and
psuedo-pregnancy
Clues for demystifying panda reproduction can
be found in surprising places. By testing giant pandas’
waste products, Zoo scientists and their colleagues
can, without bothering their charges, determine when
female giant pandas are ready to breed. This information
is crucial for zoos hoping to breed pandas because females
are fertile for only one to two days each year. Zoo
scientists track urinary estrogens to pinpoint ovulation.
For example, urine samples from the Zoo’s Mei
Xiang contained peak levels of two reproductive hormones
on April 26, 2002. The next day, male Tian Tian made
his strongest advances toward Mei Xiang, attempting
to mount her repeatedly. Fecal samples taken from zoo
pandas in China similarly reveal elevated hormone levels,
indicating when females are ovulating and ready to mate.
Hormone readings also are helping to solve interesting
puzzles for scientists because giant panda females that
don’t conceive are believed to have “pseudo-pregnancies,”
during which time their hormone levels rise similar
to those of pregnant pandas. National Zoo and San Diego
Zoo scientists also analyzed urine and fecal samples
and determined that perhaps 20 percent of Chinese zoo
pandas show no hormone changes at all, skipping one
or more years of ovarian cycling. The reason remains
a mystery that they someday hope to solve.
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Artificial Insemination and
Cryopreservation
Given the great challenges in breeding giant pandas
in zoos, zoo scientists hedge their bets by using medical
techniques, especially artificial insemination and cryopreservation.
In 2001, National Zoo scientists visited the China Conservation
and Research Center for the Giant Panda at the Wolong
Nature Reserve. With Chinese colleagues, they initiated
a study comparing how giant panda sperm fared when collected
and cryogenically preserved, under both field and laboratory
conditions. Preliminary results indicate that giant
panda sperm can be easily prepared and cryopreserved
both in the lab and in the field, and still retain the
same potential for fertilizing eggs, although cryopreserving
may slightly decrease the longevity of the sperm. This
can be overcome by using more sperm when inseminating
a female, or fertilizing eggs in the laboratory. Scientists
hope to create a centralized giant panda sperm bank
from which samples can be genetically matched and shipped
to females, near or far, for artificial insemination.
This effort greatly contributes to conservationists’
efforts to make the zoo giant panda population self-sustaining.
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TanqjiaheRiver.jpg)
Support for Giant Panda Reserves
Scientists estimate that perhaps 1,100 wild giant
pandas remain in about 25 separate populations, mostly
scattered across parts of China’s Sichuan and
Shaanxi provinces. China maintains a reserve network
to protect some of these areas, but many reserves are
understaffed, poorly surveyed, and vary in how well
they are protected. The National Zoo supports China’s
conservation of wild pandas in several ways. First,
Zoo scientists share their knowledge with Chinese scientists,
through training courses, joint studies, and data sharing.
Also, Zoo scientists work with Chinese colleagues to
find ways to involve local communities in protecting
pandas in and around the reserves. In addition, the
funds with which the Zoo secures the loan of pandas
Tian Tian and Mei Xiang—about $1 million each
year for ten years—boosts Chinese panda conservation
efforts. The first years’ funds, for example,
helped Chinese conservationists initiate education programs,
refurbish facilities, and strengthen panda monitoring
and protection efforts in three underfunded reserves.
ZooGoer 32(2) 2003.
Copyright 2003 Friends of the National Zoo.
All rights reserved.
