Research at the Lemur Center - a matter of taste

Photos by David Haring
Lemurs enjoy their choice of beverages!

People often ask what kinds of research we do. We have many projects in progress at any one time, and I will periodically introduce new and ongoing studies and post updates so that folks can get a sense of what we are learning from these animals and how. Let's start with a simple yet important study that one of our Primate Technicians, Erin Nemecek, has just undertaken to identify taste preferences in our different lemur species. As you might imagine, our lemurs get sick from time to time with anything from parasites to an infected wound, and they need to take medicine in order to heal properly. Like most of us, the generally don't like medicine. And, not surprisingly, there is really no information in the literature about lemur taste preferences. So we if we can figure out a flavoring to add to the medicine so that the lemurs will take it readily, that means that they don't have to be caught to be medicated, which makes them happy. And it also means that we can ensure they consume all the proper dose so they get better - which makes us happy!

"We are supposed to drink this, right?"

What is a lemur's favorite flavor? Groovy Grape? Mandarin Orange? Peaches n' Cream? Mom's Banana Bread? Erin obtained a number of liquid flavors from the Flavor Rx Institute (which was kind enough to donate the flavors!), including both sugar and salt solutions that can be used as the foundation for any of the flavors. She is going to run tests on different animals to see which of the flavors the different species prefer so that they can be more easily medicated when necessary. We are starting with animals representing five genera: Lemur (Lemur catta, the ring-tailed lemur), Propothecus (Propithecus coquereli, Coquerel's Sifaka), Varecia (Varecia variegate rubra, the red-ruffed lemur), Daubentonia (Daubentonia madagascariensis, the aye-aye), and the Eulemur (Eulemur mongoz, the Mongoose lemur.) Each study animal will be offered 3 ml of the flavoring in a disposable Dixie cup, and the amount consumed after one minute will be measured. Each animal will be offered a single flavor each day for the three consecutive days and their preferences inferred by how much of the solution they consume.

Mongoose lemurs use their little lemur hands!

The first step is to start working out the project parameters for the study, and so we will do a few tests with non-subject animals to figure out the best way to conduct the trials. Erin and I started with Mongoose lemurs on 12/2/2008 and used two pair: Felipe and Moheli, and Pedro and Maddie. Instead of the flavors that we will use in the later trials, we just started with juice that we know they like to get an idea of how things will go. Then, once we see that our test system is working, we'll present the actual flavors to test-subject animals. David (Research Technician) made some wooden cup holders with a stable base that a Dixie cup will fit into, and the idea was to just put the solution into the cup, put the cup into the base, and set it on the floor of the cage. Of course, the mongoose lemurs like to use their little lemur hands, and Felipe managed to take the cup right out of the base. Then Moheli took it away from him and dropped it on the ground, making it impossible to measure how much was consumed. We discovered that if we cut the cups down to right below the lip of the base, they can't get them out and instead drink from the cups, so it looks like that's what we'll do.

Please, may I have some more?

Erin and I continued testing on the rest of the species, with Varecia (Galaxy and Comet) and Propithecus (Lucius and Irene) and Daubentonia (Lucrezia) and Lemur (Nemo and Agathon.) It seems that every lemur is different. Who knew? It turns out that Em, Pvc, and Dm could and did remove the cup from the holder, but interestingly - all in different ways. Mongoose lemurs use their hands, Sifaka just smash their faces so far down into the cup that when they lift their heads, the cup pops out and they then run off with it, and the aye-ayes use their teeth to remove the cup before scampering away. Trimming the cups down was effective for the mongoose lemurs, but not good enough for the props. Taping the cup to the bottom of the holder worked for the props, but was not good enough for the aye-ayes. So David is going to make a special base for the aye-ayes, and then we can start the project in earnest. The Varecia and the Lemur catta didn't mess with the equipment at all. They just smiled and said, "Ahhhh! Juice."

blog by Sarah Zehr