: buttock) are two rounded portions of the exterior anatomy of most mammals, located on the posterior of the pelvic region.

The masses of the gluteus maximus muscle are separated by an intermediate intergluteal cleft or "crack" in which the anus is situated.

The buttocks allow primates to sit upright without resting their weight on their feet as four-legged animals do.

While human children generally have smooth buttocks, mature males and females have varying degrees of hair growth, as on other parts of their body.

Females may have hair growth in the gluteal cleft (including around the anus), sometimes extending laterally onto the lower aspect of the cheeks.