Posted on Wednesday, January 13th, 2021
It is just another day in Cleveland Metroparks Zoo’s Endocrinology Lab, when an animal keeper or curator pops his or her head in and asks if we can talk about the Zoo’s female fishing cat. They tell me the team wants to pair the female cat with the male for breeding but would like to know more about her reproductive cycle and activity.
As the Zoo’s Endocrinology Lab Manager, who works each day with animal care staff to study the physical health of our animals, my first thought is, “Sure – I know nothing about fishing cat breeding but time to learn something new today!” As a visitor to the Zoo, you may not even be aware there is an endocrine lab at the Zoo. The lab is located in the Sarah Allison Steffee Center for Zoological Medicine, the building near the rhino habitat.
The first steps in the fishing cat story are to see if anyone in the world has done research about this animal. If I am lucky there will be a good endocrine paper telling me everything I need to know about the fishing cat’s reproductive system. Sadly, most of the time I am not so fortunate. Google and a scientific literature search have found nothing. Well, time to roll up my sleeves and get to work – we are starting at square one. We ask the keepers to collect fecal samples three times per week and then let the fun begin…
I am sure if you were to open up a freezer door and see a bag of fishing cat poop, you would be immediately grossed out. When I open the freezer door and see the same bag of poop, I see a bunch of secrets to unlock. I can extract steroid hormones such as glucocorticoids, which are produced by the adrenal gland, and reproductive hormones like progesterone and testosterone. From that one poop sample I can even extract protein hormones, such as insulin. I can figure out what information an animal’s body was sending on a certain day. I can pick up patterns by developing a hormone profile. It just takes time, patience, and good pipetting skills. (And, yes, it can get smelly.)
There are many steps between receiving that poop sample in a bag and providing the answer to a curator’s question. In the endocrinology lab, I freeze dry all the fecal samples that come through the door. This is a process that draws out all the water from a poop sample. At this point the sample is crushed into a powder and becomes stable for long term storage. Now that my fishing cat fecals are all dried and crushed, they need to be weighed out. In most cases, methanol is then added to help draw out the steroid hormones. Since there aren’t any data available on whether or not methanol will work, I may have to troubleshoot and try something else, like ethanol, to do the trick. Investigative science at its best.
To answer this one question for the staff, the lab will need to look at progesterone and estrogen. These two reproductive hormones will help paint the picture if this female is cycling normally, irregularly, or not at all. This is done by running a test called an enzyme immunoassay (EIA). The physical EIA test is a small plastic plate with 96 tiny wells on it. We use a tool called a pipette (it’s like an eyedropper) to lift a precise amount of each sample into each of these wells. We need to move quickly to make sure all samples are in the solution for an equal amount of time. If all 96 wells aren’t nearly perfect than the EIA test will need to be run again. As I like to tell the students I am training, “No pressure!”
If we need to know progesterone levels to answer our fishing cat question, there is a known amount of progesterone on the EIA test and that is measured against each poop. If the keeper staff has collected fecals three times per week for a three month time period, I would have 36 samples. These 36 points are a starting point to paint that hormone profile. If the data show that this fishing cat is cycling normally, we will be able to tell if she is pregnant and predict a window of time when she will give birth. If the data show that the animal isn’t cycling normally, we take a step back with the team and look if there could be a husbandry or diet change that might better support reproductive health. All of this information from one poop sample (well, 36 poop samples!).
In any given time, the CMZ endocrine lab could be monitoring up to 12 different females in the Zoo. Next time you walk pass the tiger exhibit, ask yourself, “Could Zoya be one of the animals whose hormones we are monitoring?” The little lab in the Steffee Center couldn’t have produced so much work for management and research without the help of two amazing zoo volunteers. These two volunteers have been with the lab for more than eight years. They know their way around the lab and what steps we are on with each project. They even know the animal’s ID numbers better than I do! These ladies have become not only my volunteers but I am proud to call them my friends. We have done lots of bonding over our bags of poop. I think that is what makes work so special at times.
Through the years, I have trained undergraduate to doctorate students and everyone in between. An elephant keeper even shadowed in the lab to see the whole process. I have assisted countless researchers on various projects from measuring insulin in black rhinos to assessing cortisol in ambassador animals. I work quietly behind the scenes; tucked away in the room with all the scary signs about radioactivity and not eating and drinking in this room. I have seen students and even supervisors come and go, but my dedication to growing Cleveland Metroparks Zoo Endocrinology Lab has stayed the same. If I can make a keeper’s job a little bit easier, have data to address a welfare concern or assist with getting a cute baby on the ground, then it was all worth it.
This blog was written by Laura Amendolagine, Cleveland Metroparks Zoo