All in the family
Hey everyone! It’s Caleb with the Elephant Care Team here again! What do you think elephants, manatees, and rock hyraxes all have in common? It’s that they’re all related! Today, I’m going to break-down the African elephant’s taxonomic, or scientific, classification and explain a little bit of their ancient ancestry!
In case you don’t remember your taxonomic levels from high school biology, here’s a reminder: Domain, Kingdom, Phylum, Class, Order, Family, Genus, and species. To knock-out the four highest levels, elephants are in the Domain: Eukaryota, the Kingdom: Animalia, the Phylum: Chordata, and the Class: Mammalia, which basically means they are multicellular animals that have a backbone with a nerve cord that have hair, give live birth, and nurse their young.
As we focus on the more specific taxonomic levels of elephants, it gets a little interesting. It was once thought that elephants were classified as “Pachyderms” with rhinoceroses and hippopotami for their thick skin and large size; however, the fossil record, anatomical evidence, and molecular data suggest that they are not! Elephants, both African and Asian species, are in the order “Proboscidea” which is named for their trunk, or “proboscis”. The closest relative to elephants are manatees and dugongs, which are in the order “Sirenia.” Together, Proboscidea and Sirenia make up a special group between Class and Order called, “Tethytheria,” and the closest living mammals to Tethytheria are the hyraxes (Order: Hyracoidea). All three of these groups have completely different external appearances and live in totally different habitats. Elephants are the largest living terrestrial (or land-dwelling) mammals, manatees and dugongs are strictly aquatic, and hyraxes are rabbit-sized and live in rocks. One anatomical example that shows their relatedness is in their wrists! In all three of these animals, the wrist bones are arranged serially (as if they were into structured into columns and rows) like square floor tiles, whereas most mammals’ wrist bones are staggered, like bricks in a wall.
In the Proboscidean order, there are two living members: African elephants and Asian elephants. They are both in the Family “Elephantidae” and Subfamily “Elephantinae”, but they are in two separate Genuses. African elephants are in Genus Loxodonta and Asian elephants are in the Genus Elephas. Another member of Elephantinae that has since become extinct is the mammoth! Interestingly, the Asian elephant is more closely related to mammoths than to the African elephant, as the common ancestor of both species had separated from African elephants when they left their origins in Africa.
Within the African elephant genus, there are two species. The African bush/or savanna elephant (Loxodonta africana) and the African forest elephant (Loxodonta cyclotis). Here at Zoo Atlanta, Kelly, Tara, and Msholo are all African bush elephants.
Keeper I, Elephants