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Wednesday, Feb. 22, 2006
By ROWAN HOOPER
* Japanese name: Uchida zarigani
When they have the urge to mate, males locate a female by sight and smell. They then catch the female and hold her tight with their pincers and transfer sperm to her. The female then hides away on her own under rocks, and her eggs develop within her. A few weeks later, she lays a clutch of large eggs. Any eggs that were not fertilized, the female discards. She keeps the rest safe under her abdomen until they hatch.
Juvenile crayfish stay with their mother for several weeks, depending on the temperature. If it is warm they grow more quickly and leave sooner. As they grow, they need to shed their exoskeleton and expand. Very young animals can do this daily, but as they age, molts take place less frequently. A sluggish, slow-moving crayfish is a sure sign that a molt is about to take place. Calcium is extracted from the shell and kept internally. The animal then fans its legs and the carapace splits. For a day or two after molting, the soft animal is vulnerable to predators.
PHOTO COURTESY OF BIO-IMAGE NET