Can ring-tailed lemurs assign value to objects?

Brain power

Matilda isn’t your average ring-tailed lemur. Like many members of her species, she began life as a household pet. No longer able to properly care for her, Matilda’s owner donated the lemur to the Zoo. Now she’s “living the life” behind the scenes with world-class veterinary care, nutritious food, ample room to explore and ropes to climb on. And twice a week, she’s brought a touchscreen computer.

This tech-savvy prosimian is part of a pilot research project conducted by Dr. Darby Proctor, an animal behaviorist at Florida Institute of Technology.

“My team and I are trying to figure out if lemurs can assign value to objects,” Proctor explained. “We started out trying to get her to associate the screen with a reward. When she touched any part of the screen, treats would come out of a dispenser on the side.

“Once Matilda made that connection, we put a circle on the screen. She’d tap the circle, treats would come out, the circle would move to another part of the screen, et cetera.

“Now we have two distinct shapes on the screen. She’ll get a treat if she taps either of the shapes, but one shape yields more treats than the other. She’s still getting the hang of this stage. The whole thing is a very positive, non-invasive experience for her.”

If successful, Proctor hopes to replicate the experiment with the Zoo’s all-male ring-tailed lemur troop.

“Not many people have studied lemur cognition, so there’s potential to do some groundbreaking work here,” she added. “Lemurs are more distantly related to humans than other primates. They rely heavily on their sense of smell, as opposed to the more cognitively complex apes and monkeys that rely primarily on vision and touching.”

A key difference between lemurs and the “more advanced” primates became evident in the very early stages of the research process. Proctor had used a pressure-sensitive screen for a similar project involving the Zoo’s spider monkeys, who preferred to tap the circles with their fingernails. Thinking a lemur would do the same, Proctor brought the same screen to Matilda’s first training session.

“Instead of using her nails, she tapped the screen ever so gently with her nose,” Proctor said. “We tried putting honey on the screen to get her to use her hands and tap harder, but that didn’t work. Eventually, we bought a different kind of screen that was designed for humans wearing gloves. There’s been a bit of a learning curve here.”

One question remains: why train a lemur to use a computer?

“Because Matilda was a pet, we’re not sure if she has the social skills to live with other lemurs,” said Michelle Smurl, the Zoo’s director of animal programs. “They live in female-led societies, so we worry that if we introduced her to the males, she would beat them up or they would beat her up. Training is a good way to keep her mind active and engaged for the time being.”

Lemurs on the edge

Ring-tailed lemurs are common in zoos across the globe, but their wild counterparts sit on the precipice of extinction. A recently published paper estimates that no more than 2,400 individuals remain in their native Madagascar, citing habitat loss, collection for the pet trade and hunting as primary causes for the decline.

“I know this sounds morbid, but we want to learn as much about these animals as we can before they disappear forever,” Proctor said. “This is more of a psychological study than a conservation one, but I’m hoping some of the things we learn can be used to protect lemurs in the wild. For example, if we discover that they have an aversion to purple objects, conservationists could place a purple fence around a particular area to keep the lemurs away from dangerous situations.”

Smurl hopes Matilda’s story will encourage others to take action for lemurs.

“I’ve been working with lemurs for decades, so they have a special place in my heart,” she said. “They’re amazing, intelligent creatures and it would be an utter shame to see them go extinct in our lifetime. We may live on the other side of planet, but we’re not powerless to save them.”

Change the world with your change
One of the organizations presently featured by the Zoo’s Quarters for Conservation Program is Conservation Fusion, a non-profit dedicated to protecting global biodiversity by educating and engaging local communities. Conservation Fusion is currently working with students and teachers in Madagascar to plant trees, which will provide critical forest habitat to lemurs and countless other species found only on their island.

On your next visit to the Zoo, consider using your token to “vote” for Conservation Fusion. If you’re feeling extra charitable, you can place real change and dollar bills in the kiosk, too!