Smithsonian National Zoological Park l Friends of the National Zoo



The Cub's 40th–45th Weeks

May 12: Panda Pounds

Tian Tian's weight has been fluctuating between about 275 and 287 pounds; Mei Xiang's ranges between 237 and 249 pounds. The ten- to 12-pound daily variation is due to how much bamboo has passed in and out of their bodies. Whenever we get a weight, we like to think that the real weight would be about ten pounds lighter. Wouldn't it be nice if this were true for us! The pandas do manage to pack on the pounds even on bamboo, leaf-eater biscuits, and the small amount of produce that they are fed. We have to monitor their weights to ensure they stay fit.

Lately, Tai Shan has been the first to race out the door in the morning, making daily weighing a challenge! If he gets in Mei Xiang's way, this will prompt a swat from her to get out of the way. Since we do not get daily weights on Tai Shan we cannot document a similar variation for him, although we think he may fluctuate in the half-pound range. In addition to bamboo, Tai has been chewing on willow bark. The willow is looking rather poorly these days due to his constant attention.

May 9: Tai Is Ten Months Old Today

Tai Shan now weighs 49 pounds. When he came out of the rain yesterday, he looked like he was wearing another ten pounds of mud and water, which made him look more like the sloth bear cub. Tai Shan recently set two records at once, for staying up in the tree the longest and the latest. The record now stands at 7.5 hours and 12:30 a.m. We all shared condolences with the keeper who was stuck here late while Tai set his new record.

Mei Xiang has been pushing Tai away more vigorously, sometimes as he attempts to nurse. This is especially true when she is trying to eat. In the evenings, if and when they come in at the same time, food is usually the first thing on the agenda. My, how things have changed. Mei is now focused only on her pile of bamboo. Tai Shan persists, softly whining before settling for a dry mouthful of bamboo. Lately, he has also sampled the bamboo shoots, which the keepers provide to him as a reward for his timeliness. Then the cute factor kicks in, as he sits down with the shoot in his grasp and tries to consume it like the grownups. Tai's attention to this is short, as he soon moves on to a new mission or back to Mei, to pester her for milk or play.

May 2: Bamboo Shoots for Pandas on the Go

Tai Shan had his latest night out yet on Sunday. He went up his sycamore tree at 4:40 p.m. and didn't come down until 10 p.m. Earlier that day, after pestering Mei Xiang to play, he was sent flying off the top of the grotto with one swat from his mother. He landed with a bounce, then proceeded to climb back up to the top. This time he minded his own business.

As the breeding season continues, Tian Tian is very restless on alternate days. After spending one day power walking, he appears to need the next day off to regain his energy. Tian has discovered a high-energy snack sprouting along the fence line: tender bamboo shoots. In the wild, male pandas must really wear themselves out from sparring with other males and, if they are lucky, mating with just one female. Female pandas must avoid the males' advances by retreating into the trees until they are ready to mate. Those ever-present springtime shoots are an abundant source of protein and energy for active pandas on the go.

April 28: Tian Gets a Physical

Tai Shan has been spending more and more of his time asleep in the willow tree. This is the same tree that Mei Xiang likes to play in. We are trying to encourage him to use the water-chilled grotto at the front of the exhibit. As the weather gets hot, Tai Shan may seek out this cool spot with the help of a small piece of icy fruitcicle.

Tian Tian had an annual physical on Wednesday. The primary reason for the procedure was to collect semen to freeze and bank, for potential artificial insemination procedures both here and at other facilities. The samples were disappointing. Perhaps the quality was influenced by the fact that Mei Xiang has not experienced an estrus this year, or perhaps it was due to normal daily variation, and it was just not a good day for sperm. In addition, Tian Tian had a thorough physical that included teeth cleaning, complete radiography and ultrasound of his abdomen and chest, as well as the usual blood draws and measurements. Tian also received his vaccinations for rabies and distemper. The entire procedure went very smoothly. Tian was very sleepy the rest of the day and was given half rations that evening.

April 24: Tai's Tool Use?

Tai eating bambooTai Shan weighed in over the weekend at 47 pounds. We have seen him eating grass he pulled up in the yard. Tai sat against the fence and consumed it while resting his back. Pandas have perfected the art of eating and slouching.

Tai Shan has been able to climb over several tree guards in the past few days. At last he has been able to satisfy his desire to explore more trees in his quest for the perfect sleeping space. It was very exciting to see him use a plastic milk crate to climb up into a tree. Could we be documenting the first case of tool use in a giant panda, as well as more evidence of Tai Shan's innate brilliance?! Well, as it turns out, Tai was playing with the crate when it rolled away and down the hill, to rest by chance beside the trunk. No tool use, but lots of fun time.

Tai also recently figured out how to climb down inside a large tree guard and hide out for a while. We would still want to discourage Tai from spending time in the trees with the guards still on them. Dressed with metal sleeves, perhaps they will remain less attractive for a while longer. We want to minimize the damage, as we cannot afford to replace these large trees. Tai has recently spent a few late nights in his well-used sycamore, as well as his old river birch tree, so thankfully they are still his preference, at least for now.

April 19: Walk This Way

We have seen Tai Shan display an interesting behavior. When he approaches Mei Xiang, he will sometimes back up into her. We have also noticed this behavior when we walk toward him in the yard. He will stop in his tracks and stare at us. As we approach, he will swivel around and watch us from a sideways stance. As we get even closer, he will present his rear end and also back into us. This demeanor is quickly followed by a lunge for our legs, which we foil with toys.

In many species the rear presentation is considered submissive behavior, and there are probably elements of this in Tai's version. It also may simply be a way to initiate play. However, we also have seen him take this approach when given a tub of water for the first time, so perhaps he is also just being cautious and presenting his very padded end first, on those rare occasions when he is not quite so sure of himself. In the case of the tub, he backed up slowly, only to dip one hind foot lightly to break the surface of the water before turning his attention to more ordinary pursuits.

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