Our chins appear to be an evolutionary side effect

Male nipples. Whale pelvic bones. Vestigial hind limbs in snakes. Evolution is full of features that look purposeful. But upon closer inspection, science tells us that they are actually by-products of development and shifting gene expression. New research suggests the human chin may be one such evolutionary spandrel, a term biologists use for a trait that emerges as a consequence of other changes rather than as a direct adaptation. For decades, scientists have assumed the human chin must serve..