TURTLES 



Most of our Michigan aqu.uic reptiles are turtles. Many of our 

 turtles feed entirely in the water and go away from it only to lay 

 their eggs. Many come out far enough to sun themselves, but even 

 they pick a site on some floating log where a few steps will enable 

 them to plunge back into their protecting element. 



The shell of the turtles is a unique and typical feature of their 

 anatomy. The back is protected by a series of fused bony plates 

 (called the carapace) rigidly attached to the backbone and curved 

 to form a protecting box. The underside of a turtle is protected by 

 a rather flat shield (called the plastron) which is also composed of 

 flat plates of bone fused together. The plastron is joined to the 

 carapace at either side between the front and hind legs. When a 

 turtle is on the defensive, he pulls his head and forelegs back 

 through the front hole in his armor and his tail and hind legs in 

 through the rear opening. His feet, tail and head are protected by 

 heavy skin and scales which serve to guard the holes. In the case 

 of two species which are terrestrial, Blanding's Turtle and the Box 

 Turtle, the plastron is hinged and can close so tightly as to protect 

 the entire body beneath a bony shield. The Musk Turtle also has a 

 hinged plastron but cannot effectively close up his shell. However, 

 in the late summer all these turtles are so fat that the doors of their 

 shells cannot close. 



The heads of turtles are armed with more or less highly devel- 

 oped bony ridges which enable them to give a powerful cutting 

 bite. The toenails are well developed and sometimes very long. 

 Those of the forelegs are used to hold food and, in the case of the 

 Painted Turtle, in courtship. 



In captivity turtles will sometimes develop fungus around the 

 eves or mouth or in wounds. For treatment see Appendix 3. This 

 fungus often results from the water's being polluted or from a 

 lack of provision for the turtles to dry and sun themselves. One 

 end of the aquarium, not just a stone island, should be built up so 

 that there is some dry land. A sloping landing place of rough stone 

 or wood should run from the land down into the water. 



[85] 



