Japanese Mitten Crab


Take the lid off and look into the observation box. You will find a Japanese mitten crab, which has long and soft fur on its claws. This fur is a distinctive of this crab. You can tell this crab apart from others by finding these fur-covered claws.

You can find Japanese mitten crabs in various rivers in Japan. Its shells can grow to be 6 cm in length, which is relatively large among freshwater crabs.

It goes down the river at the beginning of fall and spawns at the mouth of the river.  The newborn baby is called larvae and they go into the ocean and live as planktons.  Once it becomes a megalopa larva and starts to take shape of a crab, it goes back up the river.  Its mobility is extremely high and it is capable of climbing to the high ends of the river.

In Kagoshima, these crabs are often called “Yamataro Crab” and are eaten. Fishing for yamataro crabs going down the river has become a seasonal tradition of fall. In mountainous regions, there are restaurants that offer yamataro crab dishes. To make this possible, infant crabs raised from eggs laid by parent crabs are released into the river to maintain its numbers.

Creatures of this water tank