How Did Elephants Evolve Over 60 Million Years?

Sixty million years ago, in what is now Morocco, an animal the size of a large dog walked through desert scrub with front teeth just barely larger than a normal jaw would need. Eritherium weighed about as much as a border collie and carried no trunk, no tusks worth the name, and nothing that would suggest it was the root of every elephant that has ever lived. Yet every living elephant, and every mammoth and mastodon before them, traces back to an animal built roughly like that one.

The short answer

Elephants evolved from small, hoofed ancestors through a sixty million year lineage called Proboscidea that eventually produced at least 180 species spread across Africa, Eurasia, and the Americas. Most of that dynasty tried radically different body plans, shovel jaws, downward-hooked tusks, hippo-like swamp bodies, before the winning combination of a long trunk and long tusks locked in and drove the group toward ever larger size. Mammoths, mastodons, and even sheep-sized island dwarfs all descend from that same experiment. The three elephant species alive today are the only branches still standing.

A dynasty of 180 species

The technical name for the whole group is Proboscidea, taken from the proboscis, meaning the trunk. Over sixty million years that lineage produced at least 180 species and spread across Africa, Eurasia, and both North and South America. Only Australia and Antarctica never hosted one. Today's three elephant species are what remains of a group that once filled the large plant-eating role on four continents.

Strange early experiments

The early branches of that dynasty look almost nothing like a modern elephant. Around thirty-seven million years ago, Moeritherium lived in the swamps of Egypt, a heavy, hippo-shaped animal with eyes and ears set high on its skull for a life spent mostly underwater. Deinotheres carried tusks that curved downward and backward out of the lower jaw like a pair of hooks pointed at the ground. Platybelodon, nicknamed the shovel-tusker, had a lower jaw flattened into a broad scoop of fused teeth built for stripping water plants. For tens of millions of years, evolution tested a dozen contradictory shapes for the trunk and tusks before settling on anything close to what elephants carry now.

Why trunk and tusk won

Two features eventually proved decisive. Tusks are massively overgrown incisor teeth, and the trunk is a fusion of the nose and upper lip into one long, flexible reach. Once an animal grew large enough that lowering its whole head to the ground for every bite or drink became expensive, a long reach started paying for itself. A trunk and tusks that could gather food and water without the head having to travel gave an edge that got reinforced generation after generation, and the animals carrying that combination kept growing larger still.

Mammoths, mastodons, and the cold

The most famous branch of the family is the mammoths, close cousins of the elephants alive today. One detail from the family tree still surprises people who meet it for the first time: the Asian elephant is more closely related to the woolly mammoth than it is to the African elephant. Mammoths were built for cold climates, with dense fur, a fatty hump, small heat-retaining ears, and tusks that curved into spirals up to four metres long. Mastodons were a separate, older branch that browsed the forests of North America, carrying blunt, cusped teeth suited to crushing twigs and soft plant matter rather than grinding tough grass.

Island dwarfs and a Cyclops myth

Some branches of the family went the opposite direction. When elephants became stranded on Mediterranean islands, including Sicily, Malta, Cyprus, and Crete, they shrank over many generations, because a body built for six tonnes on the mainland becomes a liability on an island with little food and no large predators to fend off. Palaeoloxodon falconeri stood barely a metre tall at the shoulder and weighed less than a large pig, a full elephant body plan compressed into the size of a sheep. Its skull carried one large central opening, the socket for the trunk. Some scholars have suggested that ancient people who dug up skulls like this, saw a single huge hole in the middle of the face, and built the myth of the one-eyed Cyclops around it.

How recently the giants disappeared

The end of this dynasty was fast and recent by evolutionary standards. Mammoths and mastodons vanished across most of the Northern Hemisphere between roughly 12,000 and 4,000 years ago, as the climate warmed and human hunters spread across their range. A marooned population of mammoths on Wrangel Island in the Arctic Ocean survived far longer than the mainland herds, still alive around 1650 BCE. By that point the pyramids of Giza were already a thousand years old, which means mammoths and Egyptian civilization briefly shared the same planet.

What the numbers show

• Proboscidea produced at least 180 species across sixty million years.
• The earliest known ancestor, Eritherium, lived about 60 million years ago and weighed roughly as much as a border collie.
• The dwarf elephant Palaeoloxodon falconeri stood barely a metre at the shoulder.
• The last mammoths on Wrangel Island survived to roughly 1650 BCE, a thousand years after the pyramids of Giza were built.

Glossary

Proboscidea

The scientific order containing elephants and all their extinct relatives, named for the trunk.

Incisor

A front tooth; elephant tusks are incisors that grew continuously into long, curved weapons and tools.

Island dwarfism

The evolutionary shrinking of a large species stranded on an island with limited food and few predators.

Proboscis

A long, flexible snout or trunk; the feature that gives Proboscidea its name.

Related field notes

• All Elephants field notes

Trunk, tusks, and grinding teeth are not separate inventions. They are the surviving pieces of one long experiment that once filled four continents with giants. Elephants Decoded traces that experiment from Eritherium's small, unremarkable body all the way to the three species still walking today.