Who Dung It? Solving Mysteries in Reproductive Physiology
Posted at 4:46 pm November 7, 2006 by adminZoo InternQuest is a career exploration program for high school students. For more photos see the Zoo InternQuest Photo Journal. To meet the Interns, read the Intern Profiles.
In the Reproductive Physiology Division at CRES, the Zoo InternQuest interns spent a lot of time in the Endocrinology Lab last Wednesday. Here the staff use non-invasive techniques for collecting samples such as saliva, feces, and urine which allow them to examine the hormones levels in an animals’ system.
Hormones are controlled in the brain and act as messengers to tell different parts of the body to do something. Through hormone tests, it is possible to tell if an animal is pregnant, about to give birth, or in heat.
We actually conducted an experiment designed to find hormone levels from animal feces! First, we had to play a little game of “Who Dung It?” in which the researchers challenged us to identify which animal was the source of each of five different fecal samples. Then, we took some feces, smashed it up, strained it, and diluted it. It was then ready to be tested for hormones. Some of the reasons scientists test the animals’ hormone levels are to look for patterns within a species or in an individual animal over time, or to determine if an animal is ready to mate.
It is important to know about animals’ hormone levels in order to manage them properly. When testing the hormone levels of a female to determine if she is receptive for mating, the results can determine if it is OK to place animals in an exhibit together. In some species, the animals will not tolerate being around each other if the timing isn’t right. Knowing the hormone levels of an animal like a clouded leopard can protect her and her mate from potential injury. Working together with the animal care staff, the work of the reproductive physiology team leads to further insight into the secrets of the animals that inhabit the earth’s ecosystems.
-Hayley, Zoo InternQuest, Real World Team
Sperms+Egg=Reproductive Physiology
At our second stop we met Dr. Barbara Durrant. She explained to us the processes necessary to freeze and unfreeze sperm and egg cells to be stored in the Frozen Zoo. Different cell types have different temperatures at which they must be frozen in order to remain viable.
Working as research technicians, we unfroze some sperm and examined them under a microscope. We then ran a mobility and dead/alive test. Much to my surprise, the mobility test that I performed is done entirely with no chemicals, or computers. Instead, everything is done by a human. Using a small calculating device, we counted the moving and non-moving sperm. The sperm sample that we looked at was not very mobile. So to “perk” up the sperm, Dr. Durrant administered pure caffeine, which promptly whipped them into action.
Most of the staff we met had Bachelor’s degrees in biology, biochemistry, or physiology. The heads of the divisions and the post-doctoral fellows have doctorate degrees (Ph.Ds). It was suggested that to enter this field, you do a lot of volunteering in places where you can get hands-on work. This is how most of them got their starts in the field. This field is not for the fecal squeamish, but because they do not need to draw blood to test for hormone levels anymore, it’s perfect for the blood squeamish!
-Ariel, Zoo InternQuest, Animal Career Team
Where Have all the Bears Gone?
One researcher, Dr. Tom Spady, spoke about populations of the world’s eight bear species. Dr. Spady specifically studies the American black bear in order to better understand the other species of bears. The black bear has a stable population in America, allowing Dr. Spady and his crew the opportunity to study the reproduction of this bear species as a model for other endangered bear species such as pandas and sun bears. Unfortunately, six of the world’s eight bear species are either endangered or threatened.
Recently, Dr. Spady visited South Dakota where he studied the “relationship between serum leptin, body weight, and body fat in semi-free ranging male black bears” across different seasons. Leptin is a protein hormone that regulates the energy intake of the body. He compared leptin and adiposity levels (body fat) to characterize the reproductive tendencies of the bears. This project was developed in order to find a way to actively stimulate the reproduction of bears in captivity. Understanding the relationship between the leptin levels and the amount of fat ties to nutrition management in the bears in captivity and can result in better breeding success.
This work demonstrates how the CRES staff working in a lab and in the field are helping with the conservation of bear species throughout the world. Panda bears are the most critically endangered bears in the world, and due to fragmentation across their habitat, inbreeding and reduced reproduction are common occurrences. Sun bears are also endangered due to habitat loss from logging, farming, poaching, and the pet trade. By researching the reproductive physiology of the black bear, we can better support the captive population of other bears to keep the population strong.
-Sarah, Zoo InternQuest, Conservation Team
You can follow any responses to this entry through the RSS 2.0 feed. Scroll to the end to leave a comment. Pinging is not allowed.
November 10th, 2006 at 9:49 am
I am so very impressed with the InternQuest program and with the fine young men and women who are learning so much about the research and work involved in caring for animal populations. Your blogs make me feel more confident that animals in the wild as well as in captivity may have a better chance at survival. The students’ blogs are interesting, informative, and very well written, and the pictures are great! Bravo InternQuest!!