One Animal’s “Trash” is a Scientist’s Treasure

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Zoo InternQuest is a seven-week career exploration program for San Diego County high school juniors and seniors. Students have the unique opportunity to meet professionals working for the San Diego Zoo, Safari Park, and Institute for Conservation Research, learn about their jobs and then blog about their experience online. Follow their adventures here on the Zoo’s website!

juliette_photo_w5If you’ve taken your dog for a walk and had to stop for a “bathroom break,” or ever cleaned out your cat’s litter box, you know what I’m talking about. Animals do it, you do it, we all do it. Talking about urine and feces can be uncomfortable and embarrassing to humans, but it’s a natural process that everyone has to engage in to remove waste from their bodies, one that holds a surprising amount of information. You may never think twice about your pet’s leavings, but there is someone who does.

Dr. Chris Tubbs, a Scientist in the Reproductive Physiology Division at the San Diego Zoo Institute for Conservation Research, is in charge of finding the valuable information within animal waste. Ever heard someone describe teenagers as “hormonal”? Hormones are chemical signals that are carried around the body to stimulate things like growth, moods, and hunger. They’re responsible for making you grow and mature, feel stress, happiness, sadness, and much more. Animals have them just like people do. Dr. Tubbs and his team are interested in a particular hormone, called progesterone, which stimulates the uterus (in both animals and people) to prepare for pregnancy. The team in the Reproductive Physiology Division measure progesterone levels in animals to find out if they are pregnant, fertile, or infertile. So, why look at poop then? Dr. Tubbs explained that it’s possible to measure progesterone levels in other things, like blood, but it would be much more difficult to gather a blood sample from a four-thousand pound rhinoceros than to swab its mouth for a saliva sample, or pick up its droppings. This is why looking at waste is the most common method for reproductive physiologists to study hormone levels. Interns had the privilege of getting to see some frozen urine and feces, as well as dried feces from Zoo animals, which is kept inside freezers for future research.

Dr. Tubbs taught us through a lab experiment that animals such as rhinoceroses, elephants, and pandas have cycles of fertility just as humans do. In order to have a good understanding of what scientists like Dr. Tubbs do, we took part in a mock assay. We were each assigned a station inside his actual lab with a different scenario to solve. My scenario was about a rhinoceros that was being introduced into the San Diego Zoo Safari Park collection. Keepers wanted to know if she would be able to have a baby. In order to figure this out, I was given two rows of test tubes, one for the number of days samples were taken from the animal, and the other, nanograms per milliliter of progesterone. I had to place a drop of dye into each test tube of each row. The liquid sample in each test tube of the first row turned a color which corresponded with the second row of test tubes. I wrote the numbers of each test tube in the first row and then the numbers of which test tubes in the second row they corresponded with. I then had to make a line graph for the data I found. My graph turned out to be a vertical zigzag pattern, indicating that the animal was fertile because its progesterone levels were rising and dropping, meaning that it was cycling. Dr. Tubbs taught me that because of what my graph showed, the answer to the scenario I was given was that yes, the rhinoceros would be able to have a baby.

Even though the subject of animal waste can bring a cringe to the nose, perhaps we should become less sensitive about the topic. After all, Scientists like Dr. Tubbs would not know nearly as much about reproduction and fertility in animals (or people!), or know when to breed them if it weren’t for the convenience of the “little gifts” your pets leave you. Because of waste and its accessibility in exhibits, scientists can easily study it and figure out when to best encourage reproduction of animals which in turn makes many of them able to keep reproducing in the future and surviving as a species. Next time you take your dog out for a walk and have to stop for a bathroom break, be thankful that your animal has the ability to leave behind a valuable clue. Your dog’s “trash” is a Reproductive Physiologist’s treasure.

Juliette, Real World Team
Week Five, Fall Session 2013