Did you know that an infant #chimpanzee has a white tail tuft until it is about 3 years old? Gorilla infants have this white patch on their rumps too! It is still unclear exactly why these great apes would need this derrière protective peace flag as infants, although evolutionary theory has suggested that it might serve as a visual cue that elicits caretaking behavior from conspecifics…

Sketch and fact contributed by Neetha Iyer
Sources:
van Lawick-Goodall, J. (1968). The behaviour of free-living chimpanzees in the Gombe Stream Reserve. Animal behaviour monographs, 1, 161-IN12.
Guthrie, R. D. (1971). A new theory of mammalian rump patch evolution. Behaviour, 38(1), 132-145.
Fossey, D. (1979). Development of the mountain gorilla (Gorilla gorilla beringei): The first thirty-six months. The great apes.
Alley, T. R. (1980). Infantile colouration as an elicitor of caretaking behaviour in Old World primates. Primates, 21(3), 416-429.
von Rohr, C. R., Burkart, J. M., & Van Schaik, C. P. (2011). Evolutionary precursors of social norms in chimpanzees: a new approach. Biology & Philosophy, 26(1), 1-30.