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Wednesday, Sept. 10, 2008

ANIMAL TRACKER

Coin turtle


Japanese name: Kusagame

Scientific name: Chinemys reevesii

Description: Also known as Reeve's turtle, this is a small reptile, growing to about 20-25 cm long (though larger individuals have been reported in Japan), whose shape is more rectangular than oval. It has three ridges (keels) running the length of the carapace from head to tail. Coloration is not a diagnostic identification feature, as Coin turtles vary greatly, with shells that may be yellow-brown, dark brown or even black, and skin colors ranging from olive to black. Most of the black animals are male. Sometimes there are yellow and white stripes along the neck. Semiaquatic, the Coin turtle has webbed toes to aid in swimming.

Where to find them: From Honshu to Kyushu and Okinawa, in ponds and streams with muddy or sandy bottoms. Also in rice fields. You may well see a Coin turtle basking in the sun on a rock or log, as they are diurnally active, foraging for food during the day.

Food: Coin turtles are omnivorous and will take insects and earthworms, frogs, small lizards, fish and aquatic plants. When they tackle pieces of food that are too large to swallow in one, they hold the item in their mouth and tear at it with their front claws until it is small enough to devour.

Special features: Cute they may be, but Coin turtles are notorious among ecologists for their hybridizing abilities. They will readily mate with almost any other turtle of their approximate size, even species to which they are not closely related. The problem with this is that it dilutes both the Coin turtle gene pool and that of the species mated with. Males don't really court females, unless you can call tireless pursuit and harassment "courtship." When females lay eggs (a small clutch of 4-6), the sex of the future hatchlings has not been decided. Instead of the sex-chromosome determinant of many other animals, these turtles have temperature-dependent sex determination. Young turtles hatch after 80 days, and are poor swimmers at first. Coin turtles are curious, and investigate anything new in their environment — maybe this is connected to the male's willingness to mate with almost any kind of turtle. They hibernate in winter. PHOTO COURTESY OF BIO-IMAGE NET



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