Only Humans Have Chins — and They Emerged as an Evolutionary Accident

A recent study published in PLOS One suggests that the human chin, a unique feature not found in other animals, emerged as an accidental byproduct of long-term evolution of the jaw in early hominins. Contrary to previous beliefs, the chin did not evolve as an adaptation to enhance survival but rather as a spandrel, a term describing a feature unintentionally produced by other adaptations. The research challenges the notion that every animal feature conferring a positive effect must have been achieved by natural selection.