The Bering land bridge comes and goes
Falling sea levels repeatedly expose a thousand-kilometre plain between Asia and America.
- When
- —
- Duration
- 420 thousand years
- Known to
- ± 500 thousand years
- Era
- Pliocene, Cenozoic
The Bering Strait is shallow — around 50 metres — so any substantial glacial sea-level fall exposes a broad plain connecting Siberia to Alaska. Once northern ice sheets begin cycling, the bridge appears and disappears repeatedly, and each opening allows an exchange of animals: horses and camels move west out of North America, while mammoths, bison, bears and eventually humans move east. It is the most consequential intermittent land connection in mammal history.