This form includes verbal or speech developmental apraxia, perhaps the most common form of the disorder. Constructional apraxia affects the person's ability to draw or copy simple diagrams or to construct simple figures. Oculomotor apraxia is a condition in which patients find it difficult to move their eyes.
Medium ones about the size of a golf ball may molt every four to six months and stay buried for about one to three months. The smaller hermit crabs may molt as often every month or even every few weeks for the tiniest ones, and may stay buried to do it for only a couple of weeks or months.
The hardened abdomen protects the coconut crab and reduces water loss on land, but has to be moulted periodically. Adults moult annually, and dig a burrow up to 1 m (3 ft 3 in) long in which to hide while vulnerable. It remains in the burrow for 3 to 16 weeks, depending on the size of the animal.