Scientists Just Solved the Mystery of Why Crabs Walk Sideways

A comparative study of 50 crab species suggests sideways walking evolved once, about 200 million years ago.

The trait appears to have emerged in the ancestor of true crabs, or Brachyura, during the Jurassic period.

Researchers say this signature movement likely helped true crabs diversify and thrive in many habitats.

The findings, published in eLife, shed light on one of the most recognizable behaviors in crabs.