Examples of vestigial structures include the human appendix, the pelvic bone of a snake, and the wings of flightless birds. Vestigial structures can become detrimental, but in most cases these structures are harmless; however, these structures, like any other structure, require extra energy and are at risk for disease.
The brain is most of the ape's main gimmicks, aside from the opposable thumb. It allows us to not die without claws, fangs, and other evolutionary benefits.
