Abstract

Geladas are an unusual primate. They eat mostly grass instead of fruit or meat. They are known as “bleeding heart monkeys” for the bright red patch of skin on their chests. They also live high in the mountains instead of in the jungle or the savanna. The air is thinner high in the mountains, so it is harder to get enough oxygen. How can geladas thrive in that environment? That’s what we wanted to find out. 

We studied the DNA of wild geladas. We found a surprising difference in how DNA is packaged between geladas from two different regions of Ethiopia. Also, we know that some animals react to low oxygen by increasing the amount of hemoglobin in their blood. But we learned that geladas don’t do that. Instead, they might have evolved to have larger lungs to help them get more oxygen with each breath.