Mouse lemurs are tiny — they weigh as much as a golf ball if the ball had giant eyes and a fluffy tail.
But because they are genetically similar to humans, mouse lemurs may provide researchers at the Duke Lemur Center with a key to unlocking the mysteries of Alzheimer’s disease. To do this, mouse lemurs need to get their tiny hands on some smartphones.
Bigger, ruffed lemurs have been using touchscreen tablets at Duke for years. Scientist Raymond Vagell uses tablets to test lemur color vision. If lemurs could see a red block on a screen of colors, understand the task and touch the red, they received dried fruits.
Though some savvy lemurs gamed the system by mashing their hands all over the screens until they hit the target, they were overall quick to catch on to using the tablets.
“Lemurs are kind of like chimpanzees, dolphins and horses,” explained Erin Ehmke, director of research at the lemur center. “They prefer to work for their food.”
It’s hard to drag the lemurs away from the tablets once they start to work on them.
The link with Alzheimer’s
Vagell’s original research with tablets spawned new ideas, one of them using mouse lemurs as models for humans with Alzheimer’s. Lemurs exhibit some of the same symptoms of cognitive decline as people when they age. They get confused and stumble. They slow down and may start walking in circles. Old lemurs might start falling from heights.
They also experience symptoms associated with Alzheimer’s. There is evidence that like humans, mouse lemurs can develop a buildup of sticky proteins between neurons in the brain as they age. Fibers essential for neuron functioning can become tangled and useless.
Similarities between mouse lemurs and humans made the researchers want to know more about how their brains function throughout their lifetimes. The fact that mouse lemurs live to be about 12 years old in captivity means researchers can examine the aging of entire generations.
“We like to stress that the work we do is non-invasive,” said Meg Dye, the Center’s curator of behavioral management.
So, instead of using invasive procedures to get inside lemurs’ minds, the crew is trying smartphones.
Smartphones for tiny lemurs
Dye walks to a low-slung building where nocturnal mouse lemurs are housed and opens the door. The hallway is bathed with red light— it’s bright enough for people to work, but doesn’t expose the lemurs to daytime conditions. High pitched squeals echo through the building. Dye turns to a door labeled with lemur names such as Oleander and Thistle, and turns the key.
Inside a small room, cages cover the walls from floor to ceiling. Dye explains that each mouse lemur has a tower with two or three stacked cages to live in, and fixtures they can hide in.
A few mouse lemurs head to the front of their cages to take a look, enormous eyes shining in the red light. Thin fingers with knobby tips grip perches as they stare curiously. They look cuddly and adorable, but looks are deceiving. According to Ehmke and Dye, researchers wear gloves when handling mouse lemurs because they have needle-sharp teeth. When they bite, they don’t let go.
The reason mouse lemurs need smartphones is simple: they can’t reach high enough with their short arms to use the larger tablets already committed to ruffed lemur trials. When they have enough Android phones from donations — only Androids can run the study’s software — scientists will begin training the lemurs to get used to the phones.
Mouse lemurs are more skittish than their larger relatives, and the question remains, will they be as motivated to use the phones as ruffed lemurs?
Dye estimates it will take a year or more to train the mouse lemurs, and they are still in the process of developing cognitive tests. They’re also waiting for more phones; they have four so far. The Lemur Center hopes to have entire lemur colonies accustomed to using computers so that that scientists can perform a variety of research projects without spending time on training.
The idea of lemurs trained to use computers conjures an image of lemur armies taking over the world, and Ehmke and Dye laugh at the thought. “If there was an army of lemurs taking over,” says Dye, “it would definitely be mouse lemurs.”
How you can help
To donate used Android phones to the study, mail them to:
Duke Lemur Center
Attn: Animal Training Department
3705 Erwin Road
Durham, NC 27705