Fossils show that howler monkey ancestors were eating leaves 13 million years ago, shaping body size and evolution.

An extinct relative of the howler monkey may have been the first leaf-eating primate in South and Central America ...

Add Yahoo as a preferred source to see more of our stories on Google. Here a white-faced capuchin monkey perches on a tree branch in Manuel Antonio National Park in Costa Rica. A group from the same ...

The “big truck, small man” phenomenon is also seen in the animal kingdom. The loudest howler monkeys were found to have the smallest packages. Hyoid bone size, which is responsible for vocalizations, ...

On an island in Panama, a fad that one researcher called "viscerally disturbing" has recently taken off among a group of young male monkeys. These adolescents and juveniles have started to kidnap the ...

If you lose your sight, you make up for it with other senses. If one arm is amputated, you learn to do twice as many things with the other arm. The balancing act continues, constantly juggling and ...