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turtle - Form and function

Why do most tortoises have high, domed shells?

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Illustrations of ten representative chelonians, including spiny softshell turtle, Galapagos giant tortoise, green turtle, alligator snapping turtle, Blanding's turtle, common map turtle, eastern box turtle, eastern painted turtle, spotted turtle, and eastern mud turtle, each labeled with its common and scientific name. A scale bar at the bottom shows size comparison. — turtle Turtles (order Testudines).

Most tortoises possess high, domed shells as an evolutionary adaptation to deter predators. This specific shape makes the shell difficult for a predator to hold in its mouth and crush, providing a significant defensive advantage for these reptiles.1