When deciding on a topic to write about, it was difficult to pick just one because I’ve had many exciting experiences while working here, and each day holds new adventures and animal encounters. This summer I’ve touched a Sumatran tiger, a cheetah (which purred!), fed a rhino and a giraffe, and watched a friendly badger meander down our hallway most Friday afternoons. Every day at the Institute is an adventure, and when I walk through the doors, I never know what animal I could encounter that day. One of the days I found the most fascinating occurred Thursday, August 5….
I knew it was going to be an exhilarating day because we were headed to the Zoo for panda Zhen Zhen’s pre-shipment exam (the vets check her before we send her to China). In the Reproductive Physiology lab, we are currently working on finding a way to better understand giant panda pregnancy and a way to diagnose it earlier after breeding. Pandas only have one estrous cycle a year! This gives us only a few opportunities to breed them during their time here at the Zoo.
Pandas can also go through pseudopregnancy (or “false” pregnancy). Currently we are unable to diagnose a real pregnancy from a false one using hormone tests. This is where Zhen Zhen and Su Lin come in. We’ve taken many vaginal swab samples from Su Lin during her false pregnancy (she wasn’t mated this year, so we knew she wasn’t really pregnant). We then extract the RNA from these samples in hopes of finding out which genes are expressed when she is cycling or when she’s pregnant. This will help us to better tell a pregnancy from a pseudopregnancy. If we find out soon after breeding that a female isn’t pregnant, we may be able to inseminate the panda again before her breeding season is over for the year.
On this particular day with Zhen Zhen, we were going to use her samples as a control in our experiment because we knew she was not pregnant. Barbara Durrant, Ph.D., director of Reproductive Physiology and Henshaw Chair, also performed an ultrasound on Zhen Zhen to get a better understanding of the giant panda reproductive anatomy. To this day, no one has seen a giant panda placenta!Following the fun morning at the Zoo, we returned to the San Diego Zoo Safari Park, historically known as the San Diego Zoo’s Wild Animal Park, and to the elephant barn, where we sat and waited for African bull elephant Mabu to pee. Why were we sitting around waiting for an elephant to pee? Well, because the keepers discovered that when Mabu urinates, he also gets in the mood to breed. We then use this natural behavior for semen collection. Since Mabu and the whole herd here at the Park are from Africa, they are new to elephant collections in North America. Therefore, if we are able to collect semen from Mabu and ship it to other zoos across the country, it will help increase genetic diversity within African elephants in North America. After a collection success with Mabu, we returned to the lab.
This summer I have learned a lot about hormones and hormone assays. In the Reproductive Physiology lab, we use hormone assays, or tests, to diagnose pregnancy, estrous cycles, ensure that contraceptives are working, and measure the stress of an animal.
My summer project was monitoring stress in Stephens’ kangaroo rats (SKRs). As you know from Debra Shier’s earlier posts (see Mountain Lions Help Kangaroo Rats?), the Institute is working to expand the geographic range of these locally endangered creatures to ensure that they will not be susceptible to catastrophic events such as wildfire, disease outbreak, and flooding. My part in this project was to find out the baseline/normal stress levels for SKRs, which stress hormone SKRs produce, and if we can measure hormone(s) using feces to detect stress.
This summer I found out that SKRs produce two different stress hormones, both cortisol and corticosterone, and I characterized their nightly stress hormone pattern. With the data I’ve generated this summer, the Institute will be able to use stress hormone monitoring in the future for their translocation project to better understand how well the translocation process is going.
It has truly been a joy to work for this extraordinary organization. I will definitely miss walking through its doors every day and seeing the smiling faces of everyone who works here.
Alyssa Hall is the Wheedon Endowed Summer Fellow in the Reproductive Physiology Division of the San Diego Zoo Institute for Conservation Research.
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