The Secret Life of Lobsters - Trevor Corson

"When the lobster is ready to shed, it pumps in seawater and distributes it through its body, causing hydrostatic pressure to force the old shell away from the new one. The lobster remains mobile and active until the last minute, when the membrane that lines its old shell bursts and the animal falls over on its side, helpless and immobilized. After twenty minutes or so, the lobster's back detaches and the animal pulls its antennae, mouthparts, legs, and claws out of their former coverings, aided by a lubricating fluid. The most difficult moment comes when the lobster tugs its claw muscles out through the slender upper segments that form its wrists. Before molting the animal must diet away half the mass in its claws or risk getting stuck in its old clothes. Worse, because a lobster is an invertebrate, every anotomical feature that is rigid is part of the exoskeleton, including the teeth inside the stomach that grind food. The lobster must rip out the lining of its throat, stomach, and anus before its free of the old shell. Some die trying."