Proboscidea

Proboscidea (cohort Ferungulata, superorder Paenungulata) An order that comprises the elephants and their extinct relatives, divided into four suborders: Moeritherioidea, Deinotherioidea, Gomphotherioidea, and Mammutoidea. The mastodons are included in the suborder Mammutoidea. The suborder Gomphotherioidea includes two families, Gomphotheriidae and Elephantidae, the mammoths, modern elephants, and their immediate ancestors being included in the latter. The order was formerly highly successful and occupied the Americas, Eurasia, and Africa. Probiscideans tend toward large size. Since the late Miocene most have possessed a long trunk: this is developed from the nose and upper lip, is operated by a complex musculature, is sensitive to chemical and tactile stimuli, and is used to obtain food and water and in making sounds (which are important in social organization). Teeth are reduced in number, adults having three molars in each side of each jaw; these are used one at a time, old teeth being shed and replaced by those behind. The upper incisors are enlarged to form tusks. The jaw muscles are large, and the skull short and high. The vertebrae and up to 20 ribs carry the weight of the abdomen, which is balanced on the fore limbs by the weight of the head, the hind limbs providing propulsion. The brain is well developed. Parental care of the young is prolonged, and social organization is complex.