Elephants are the only mammals, besides humans, to have chins.
Elephants And Humans are the only two species to have chins. Although there is often debate as to whether the same term of “chin” can be used for elephants, the feature is arguably the same in both species.
In human evolution, the chin is a cladistic apomorphy, partially defining anatomically modern humans as distinct from archaic forms – apes have a simian shelf for example (a bony thickening on the front of the jaw to reinforce the jaw).
The chin developed as a point of muscular attachment for the tiny movements of the lips, associated with speech, and the human chin is formed by the lower front of the mandible (the lower jaw).