Until Now
Biology

A body built for running

Long legs, short toes, spring tendons and sweat glands make a mediocre sprinter into a superb distance runner.

When
Duration
400 thousand years
Known to
± 100 thousand years
Era
Early Pleistocene, Quaternary

Homo erectus acquires a suite of features that only make sense together for endurance running: an Achilles tendon and arched foot that store and return energy, a nuchal ligament to stabilise the head, decoupled shoulders for counter-rotation, short toes, and a large gluteus maximus. Combined with sweat cooling and hairlessness, this allows a hominin to run a quadruped to heat exhaustion over hours — persistence hunting, still practised in a few places. Whether running drove the changes or came with them is argued.

Just before

Just after