TIME

The Cambrian Explosion

≈ 539 million years ago

Illustration of a Cambrian seabed: a large Anomalocaris with grasping appendages swims above the sediment, while an Opabinia with five stalked eyes, a spiny Hallucigenia and a trilobite rest below in green light from the surface.

Earth & LifeThe Cambrian Explosion

Animal life diversifies.

Animal life diversified dramatically in the early Cambrian Period, and many major groups became prominent in the fossil record.

The Cambrian began 538.8 million years ago on the international stratigraphic chart. The diversification took 20 million years or more.

539 million years ago, placed on the scale of its era on a line leading toward now.

Era
Earth & Life
Period
≈ 539 million years ago
Edition
1/1
Status
Not Released
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Background artwork

An original illustration generated for TIME with an AI image model, 2026. An artistic reconstruction of animals from the Burgess Shale, which lived about 508 million years ago, some 30 million years after the start of the Cambrian. The animals are an interpretation drawn from fossils.