Our April Enigma
Posted at 1:41 pm April 23, 2007 by Suzanne HallI spent breakfast with Bai Yun this morning. For two hours, I sat and watched her as she ate bamboo and biscuits, and ultimately settled for a nap. As I have so many times in the last few weeks, I recorded data and watched her closely for signs of estrus. Although her behavioral indicators are not yet strong enough to suggest she is close to her peak, some of her estrus behavior is picking up.
A typical behavior pattern for a female in estrus is to decrease food consumption while increasing activity level, including restless wandering and scent marking. For the last few days, Bai Yun has shown a bit of a decrease in appetite. This morning, she left quite a bit of bamboo unfinished, something she would not have dreamed of doing a month ago. However, instead of using her spare time to wander and mark, she chose to fill her time with a nap. At least she has one half of the equation right!
Females in estrus also become a little more solicitous to males in the area, culminating in sexual receptivity around their peak. Bai Yun, who last week barked at and swatted Gao Gao when he was near, was this morning observed sitting near the howdy gate. She watched Gao Gao and chirped sweetly for several minutes. When she finished saying her hellos, she turned and left a nice scent mark near the howdy corridor before ambling over to her resting place.
Our early hormone projections suggested that Bai Yun’s estrogen would fall precipitously anywhere from Tuesday to Thursday of this week. Her strongest estrus behavior, and sexual receptivity, should follow that drop. At this point we are left to wonder: is she running a few days behind our model’s projections? Or will she surprise us tomorrow? We suspect that she will peak near the end of the week. If her hormones do indeed fall late on Thursday, then Friday would be our expected ” go” date for a first mating encounter. If multiple days of breeding are on the horizon, we could pair Bai Yun with Gao Gao that day and over the weekend.
There is another possibility to consider. Things have been a little trickier with Bai Yun this year, a bit unexpected here and there. It is possible that she will maintain this guessing game and fail to show us strong estrus behavior at her peak. Our mating decision tree dictates that, if she or Gao Gao fail to demonstrate appropriate sexual behavior towards one another, we will not pair them. This is to ensure that no fighting occurs and no bear is injured in a botched breeding attempt. Could we be looking at a year without breeding?
I don’t think so. Gao Gao appears to have picked up on something, as his behavior has ramped up in the last 24 hours. He is wandering frequently, checking the howdy gate as much as 14 times in 90 minutes, and now his bleating is more intense, his activity more vigorous. He is ready to go.
As for Bai Yun? She has never let us down before. I predict she will breed this year, at the end of this week. Remember this year’s mantra: truncation. Her behavior may not come on line for us until the last minute. One older female in Mexico City showed a behavioral estrus of less than 48 hours from start to finish when she was about Bai Yun’s age.
Some of you have asked about the possibility of an AI. If we have multiple matings, there will not be a need for an artificial insemination. The AI would only come into play if we have doubts about the success of any breeding encounters, or if none occur at all. You’ll have to stay tuned to this zoo station to find out how it all works out.
Suzanne Hall is the senior research laboratory technician for the Giant Panda Conservation Unit of Applied Animal Ecology/CRES.
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April 23rd, 2007 at 2:05 pm
Thanks, Suzanne, sounds like the watch and wait game is on in full. GaoGao is on to something. It is interesting to hear that they sit and watch each other and ” softly” chirp their greetings. If she is not at all interested in him, it would seem that she wouldn’t bother to try to communicate with him. So, at least some form of estrus appears imminent. The question is whether the humans in the mix will be clued in. Do you plan any 24 hour watches in case the ” moment” of her behavioral estrus happens during non-zoo hours? Since you need to keep the howdy gate closed to prevent any potential fighting, if no one is there to open it how will they get to do their introductions and socialization. If she is sitting near the gate more frequently, does that not indicate that in the wild she would be moving in closer proximity to Gao, or at least invite him to come closer to her? How much ” socialization” do they normally do before an actual mating takes place? Or are they all business and then part company? Do they tend to ” hang around” after a mating, or do you separate them for several hours until the next attempt? I have not seen much written about their last mating which resulted in Su Lin. I have seen a video clip of them ” in action” with the keepers excitedly and anxiously watching. I could not tell from the video how much time they were together before or after the actual mating. It seems to me that in the wild they would hang around the same general area for the 48-72 hours of peak receptivity so that they could have easy access for multiple mating attempts. Once Bai’s receptivity has gone down, it is logical that she would remove herself from Gao, and likewise would make it obvious to him that it was time for him to ” leave.”
April 23rd, 2007 at 6:18 pm
Thanks for the exciting update. I hope everything works out.