Panda Breeding Season Has Faded to a Calm Spring

Roughly a month and a half after Mei Xiang’s artificial insemination, things at the David M. Rubenstein Family Giant Panda Habitat are settling into their regular routine. For the pandas that means bamboo feedings punctuated by naps. Mei Xiang’s breeding season is finished, though Tian Tian is still showing signs of rut, and Bei Bei is growing as quickly as the bamboo shoots.  

Mei Xiang was back to her old self within a month after she reached peak estrus on March 27. Her restlessness and focus on Tian Tian have subsided a little faster in the past, but with Mei Xiang every estrus is slightly different.

Keepers started practice-ultrasounds with Mei Xiang last week to get her comfortable with the equipment and back into the routine of doing them. It is still too early to see any changes in her reproductive tract, but having an established routine will make it more likely that she will continue to participate in ultrasounds at the end of a pregnancy or pseudopregnancy when her hormonal changes make her less interested in food and interacting with keepers, and more sensitive to noise and unfamiliar people. 

Mei Xiang will not start showing any of those behaviors until she enters her secondary hormone rise, when her levels of progesterone start to spike. That rise indicates that she is 30 to 50 days from giving birth or finishing a pseudopregnancy. During that time, Mei Xiang will spend more time in her den, bringing bamboo into it and building a nest.

Tian Tian is still in rut, which is normal. Male pandas typically experience rut starting in November and come out of it in June. As a result, Tian Tian is still restless sometimes. Usually in the afternoon, he will look in the windows between his and Mei Xiang’s yards, probably looking for her.

Tian Tian and Mei Xiang have both been receiving laser therapy regularly to help arthritis in their left shoulders. Veterinarians perform the therapy on each of them once each week. During the sessions, either Mei Xiang or Tian Tian (depending on whose day it is for laser therapy) sits in the training chute and is rewarded with some favorite treats for sitting still. It seems to be going well, and they both appear to be doing fine and moving normally.

Bei Bei weighs roughly 260 pounds, making him the same size as Mei Xiang. Some days he weighs in more, other days a little less. He’s still growing, and keepers think that he will be as big, if not larger than, his father, Tian Tian.

And finally, it’s officially the pandas’ favorite season — bamboo shoot season! The shoots are like candy for the pandas, who will spend hours eating as many as they can, so they are really happy right now.