The Cub's 18th Month
December 28: Tai's Very Spiky Hairdo
On Christmas Day, the Zoo staff on duty were permitted to leave two hours early. However, this was not part of Tai’s plans for the day. He was up a tree and in the rain, until 4 p.m. When Tai finally ambled indoors, he was soaking wet and sporting a very spiky hairdo. Tai Shan still has the long fuzzy coat of a panda cub, and water makes his coat all spiky. Water drips off of the spikes, leaving his skin almost dry. The spikes around his ears make him the most endearing juvenile—and, in this case, delinquent—panda. Tai Shan weighed in at 87 pounds the next day. This was his dry weight!
Starting in January, we will begin taking weekly swabs from Mei Xiang to look at vaginal cytology (cytology is the study of cells). Over the years Mei Xiang has had one estrus in March, two in April, and one in May. Mei’s 2005 estrus was in March. Some female pandas experience estrus as early as February.
Changes in the cells from Mei’s reproductive tract help us to pinpoint the two-day peak ovulatory period, which occurs only once a year. We also monitor Mei Xiang’s behavior, as well as hormonal changes through tests on her urine and feces. We will also begin to measure Tian Tian’s testes monthly. Male pandas experience a rut or breeding season, which results in enlargement of their testicles, in addition to behavioral changes. Preparing for this annual event takes lots of planning across many departments at the Zoo. Read more about panda reproduction.
December 21: Some Treasured Memories
Tai Shan weighed 85 pounds yesterday. He will climb on and off the scale independently and for his own amusement but not on our training cue! When we watch him walk beside Mei, who currently weighs in at 214 pounds, they appear to be almost the same size. This is especially true from the rear-end point of view.
The months seem to fly by, and we are left with fleeting memories of our pandas. They fondly linger in memorable vignettes.
On one particular lovely fall day Mei Xiang was wandering through the new habitat. She started across the deadfall, which arcs high over the stream, where upon second thought, she decided to turn around. Mei had yet to attempt to cross this bridge, which requires some balance for big pandas. Along came Tai Shan right behind her. He was on a forward trajectory and there was no turning him around. Tai proceeded to force Mei to continue across, much to her dismay. Once across all Mei’s hesitancy was forgotten, as they engaged in a long play session inches away from the glass and some very delighted visitors.
Just as the pandas were beginning to explore the water, it was drained away for the winter season. Tian Tian did manage to get one good soaking in, sitting in the waterfall and swishing his feet to cool off. Just a week ago we spotted him in repose over a large log, in the most amusing position, as though he had collapsed under the influence of complete exhaustion! All we could see was his head and shoulders and forearms, as though he had taken a swan dive over the log into a deep sleep. He was draped as far over as possible without his nose and paws touching the ground. The pose was a greeting card writers’ dream image of humor.
December 20: Panda Paws
Because they lack opposable thumbs, seeing giant pandas holding bamboo in their paws might make you wonder how they do it. This radiograph image of Tian Tian's paw provides a great look at the adaptation that helps pandas eat. In addition to having five well-developed digits, giant pandas have an enlarged carpal bone (called the radial sesamoid bone) that acts as a "pseudothumb." This pseudothumb opposes the first and second digits, helping pandas grasp bamboo. See a picture of a panda holding bamboo. This radial sesamoid is present in other bears, but is more developed in the giant panda.
In 2005, the Fuji Medical Systems division donated a state-of-the-art digital x-ray system that enables Zoo veterinarians to diagnose animal health problems more quickly and accurately than with conventional film-based x-ray systems. The new equipment makes examinations much quicker and easier for the Zoo's animals by producing digital images that can be manipulated to show both bone and soft tissue and to reveal injuries that may not have appeared on a film x-ray. Thanks to Fujifilm's generosity, the National Zoo is one of the first zoos in the country to employ this technology.
December 13: Panda Messages
With the onset of cold temperatures last week, the pandas have been very active. Tai Shan discovered the ice in the pool in Yard One and spent a lot of time playing with it. Tai was strong enough to pull up a large chunk, rearing up briefly with it between his paws, before falling over. Early one morning, he delighted our devoted visitors with a play session with his now-deflated soccer ball. One down, two more to go! Tai also seems to be enjoying the trees in the new enclosures, resting and scratching up high in recent weeks. This gives Mei Xiang a big break from Tai’s very irritating mime of a giant tick hanging and bumping along beside her, as she wanders through the yards.
Tai Shan and Mei Xiang continue to encounter Tian Tian in the new chute system at the mesh dividing doors. Although both have been heard softly chirping at Tian, Tian still seems very nonchalant about it all. Food has become the focus for the pandas since our first bout of cold weather. The adults have started eating more bamboo, eating both the leaves and stalk. It is still very hard to determine how much Tai eats, but a few days ago we established a fecal record, with the discovery of a pile of 18 mini-droppings, below Tai’s sleeping spot, on the rockwork in Enclosure Three. Pandas conserve energy, even when sleeping, by not bothering to move anywhere else to urinate or defecate. These selected spots, or latrines, also serve as panda message central. If there was not a size difference, we would have a tough time distinguishing the piles... but the pandas know!
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