Did hunting cause the extinction of woolly mammoths or did populations fail as a result of vegetational changes at the end of the Pleistocene? Hunting pressure usually results in faster life histories, but nutritional deficiency causes life processes to slow down. Evidence from tusk growth records suggest that Siberian woolly mammoths were weaning earlier at the end of the Pleistocene than during the last glacial maximum. This is consistent with hunting as the cause of their extinction.