proboscideans

Proboscideans are an order of large, herbivorous mammals that includes elephants and their extinct relatives. They are characterized by a long trunk, tusks, and massive bodies with sturdy, column-like limbs. Their teeth are highly specialized, with molars that wear down and are replaced over life, reflecting a shift from browsing to grazing in many lineages.

Among them are several families, including Elephantidae (the modern elephants), Mammutidae (mastodons), Deinotheriidae, Gomphotheriidae, and Stegodontidae. The two living genera are Elephas (Asian elephants) and Loxodonta (African elephants), with species such as Elephas maximus, Loxodonta africana, and Loxodonta cyclotis. Extinct proboscideans include mammoths (Mammuthus), stegodons, deinotheres, and gomphotheres, which inhabited Africa, Eurasia, and the Americas from the Eocene to the late Pleistocene.

Proboscideans originated in Africa during the early Cenozoic and diversified across Africa, Eurasia, and the Americas. The group flourished as megaherbivores during the Miocene, Pliocene, and Pleistocene, with distinctive adaptive radiations such as tusk-bearing mammals and trunk development. Many early forms had different dentitions, but by the time of elephants their teeth were large, high-crowned and gradually replaced. The Pleistocene megafauna included mammoths and mastodons; most proboscideans disappeared by the end of the last Ice Age, with the surviving elephants restricted to parts of Africa and Asia.

Today, elephants are keystone species in many ecosystems, shaping vegetation and dispersing seeds. They face threats from habitat loss and poaching for ivory. Taxonomic classification and the precise relationships among extinct proboscideans are subjects of ongoing study, but the overall pattern reflects a long, diverse evolutionary history spanning more than 50 million years.