Photo: Invisible "Skeleton" Supports Shell-less Crab, Study Finds



A blackback crab sits next to the hard shell, or exoskeleton, the animal has just shed.

The crab's soft body should mean that the creature must lie helpless and vulnerable during the several days it takes a new exoskeleton to harden. But new research shows that the crab adapts to this dangerous period by creating an internal "skeleton" made of gas from its guts.

Photograph courtesy W.M. Kier and J.R.A. Taylor/ Nature


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