Thirteen million years ago, a group of medium-sized monkeys known for guarding their territory among the treetops with fearsome "howls" started doing something new. These monkeys, among the oldest ...

An endangered roloway monkey, Masaya, has given birth to infant Lagertha, months after pioneering surgery saved her foot from amputation. The 15-year-old monkey underwent a complex operation last ...

Humans perceive emotional expressions displayed by non-human primates and spontaneously mimic these expressions, according to ...