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Thursday, May 13, 2004

ANIMAL TRACKER

Mudskipper


* Japanese name: Tobihaze
* Scientific name:Periophthalmus sp.
* Description: Mudskippers are fish with eyes on the top of the head (not at the sides like in most other fish) and with front (pectoral) fins that are more like legs than fins. They are olive-brown in color, have sharp teeth and large mouths, and grow up to 15-cm long. The eyes can be raised on stalks, independently of one another.
* Where to find them:Mudskippers are found in the mud of mangroves and river estuaries in Honshu, Kyushu and Okinawa. They thrive in brackish water with a salinity halfway between marine saltwater and riverine freshwater. Mudskippers are unusual fish in that they can often be seen clinging to the branches of estuarine or mangrove trees, above the water line.
* Food: Worms and crustaceans (crabs and shrimps) that live in the river mud. Some mudskipper species eat algae that grow on mangrove roots; others eat insects.
* Special features: Mudskippers are amphibious fish. They have gills that work like those of other fish and extract oxygen from water, but unlike other fish, they can also breathe air. In this respect they are similar to lung fish, the ancestors of the first vertebrates to walk on land. Mudskippers absorb oxygen through their wet skin, and have sacs under the skin near the gills that act like lungs, transmitting oxygen from the air to the blood. Everything about mudskippers is an adaptation from the truly fish way of life, to one where much of the animal's time is spent out of the water. Their pectoral fins are so well adapted to use on land that mudskippers can run faster than they can swim. During the mating season, males dig mud burrows and perform acrobatics and push-ups to attract females. The dorsal fin becomes brightly colored and is flashed in warning to rival males. Females lay their eggs in the burrows, but as these are so deep, the water within them contains almost no oxygen. To ensure the eggs have enough oxygen to develop, males gulp air from the surface and release it at the bottom of the burrow. Mudskippers care for their offspring.



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