Right now we have the two sister pandas on exhibit! Su Lin will be four years old on August 2, and she is about 190 pounds (86 kilograms). She has already gone through her first estrus with flying colors and has been very active out on exhibit so far.
When we move the pandas into different enclosures, it actually works as a form of enrichment. Previously, her father Gao Gao was in her enclosure. He scent marks the enclosure quite a bit, as males will do. As Su Lin entered, she smelled a different bear and began to scent the enclosure for herself. The morning was filled with smelling the air and smelling the different climbing structures.
Many of our guests that come to see the pandas learn that the two girls in front are sisters, and it usually follows that they wonder why the two can’t be in together. A female giant panda keeps her cub with her for the first 18 months; in that time she will not cycle or come into her estrus while nursing the cub. After separating from the cub she will often have a month to two to stop lactating and begin coming into her next breeding season. The older and younger cubs have no knowledge of their relationship to each other. Zhen Zhen is two years and one day younger than her older sister, Su Lin.
You can see the two of them smell the air when the breeze comes through Panda Canyon, and I’m sure they can smell the bear on the other side of the wall. This is not the first time that they’ve been neighbors. Both girls were in our two off-exhibit classroom enclosures during our breeding season, and even then there was a lot of vocalization between the two.
Zhen Zhen is now 22 months old and about 102 pounds (46 kilograms). She has been sleeping much of the time on exhibit, but when she is awake, true to panda nature, she has been eating quite a bit of bamboo. Seeing the two girls next to each other you can really see the difference in size and behavior. Su Lin still gets very active climbing the trees and running around her enclosure, while little Zhen Zhen has been sleeping quite a bit and posing for pictures.
Su Lin will be out on exhibit for a couple of weeks, and then it will be Gao Gao’s turn to come out and have new scents to investigate!
Anastasia Horning is a panda narrator at the San Diego Zoo.