Monkeys and apes are both primates, which means they’re both part of the human family tree. As distinguished relatives, we should probably be able to tell them apart. But when you look at a gibbon or a marmoset, how do you know which is a monkey and which is an ape?

The two words have different language origins, but they have often been used interchangeably in translations and popular culture. Even past versions of academic resources, like the 1910 edition of Encyclopaedia Britannica, have indicated that "ape" and "monkey" are synonymous. To understand the scientific differences between an ape and a monkey, ...