The Kid Should See This

Hermit crabs line up to exchange their shells

There’s an extraordinary sight in this clip from the BBC’s Life Story, narrated by Sir David Attenborough: A line of hermit crabs self-arranges from smallest to largest. They’re ready and waiting to exchange their shells—but why? Attenborough explains that “as a crab grows its shell becomes an ever-tighter fit so eventually the crabs need to move into a bigger one.” And so these small decapod crustaceans have organized, hopefully ensuring that each one will quickly find and move into a slightly larger mobile home.

hermit crabs in a line
hermit crabs exchange shells
Related videos: Pagurus Bernhardus changes its shell, a Caribbean hermit crab named Godzilla, a Caribbean hermit crab mass migration, and more videos about crabs.

Also: A molting Japanese spider crab time lapse.

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