great ape

Their study suggests that the mouth-on-mouth kiss evolved more than 21 million years ago, and was something that the common ancestor of humans and other great apes probably indulged in.

That view shifted when researchers analysed 51 fossil teeth from a range of hominids and great apes, including Australopithecus africanus, Paranthropus robustus, early Homo, Neanderthals, and Homo sapiens.

These included seven hominid species, or "great apes,"** such as humans, gorillas and chimpanzees, and nine hylobatid species, or "lesser apes,"*** such as gibbons.

The samples included both modern and archaic humans such as Neanderthals, early human ancestors like Australopithecus africanus, and extinct great apes including Gigantopithecus blacki.

The researchers are currently developing its use in sanctuaries for great apes, including chimpanzees and gorillas.