Geochelone nigra  (Testudinidae)

Remarks: There are 14 described subspecies of the Galápagos tortoise of which 11 still exist, some with only small populations. There are “dome-shelled” and “saddle-backed” tortoises.

Distribution:  Native to seven of the Galápagos Islands. Habitat: On islands with humid highlands, the tortoises are larger, with domed shells and short necks. On islands with dry lowlands, the tortoises are smaller, with saddleback shells and long necks. Habitat: Domed tortoises live at higher altitudes in thick shrubbery which is also their food.

Appearance: They have a large bony shell (carapace) of a dull brown color. The plates of the carapace are fused with the ribs in a rigid protective structure that is integral to the skeleton. Lichens can grow on the shells of the slow-moving animals. Tortoises keep a characteristic scute (shell segment) pattern on their shell throughout life, though the annual growth bands are not useful for determining age, because the outer layers are worn off with time. A tortoise can withdraw its head, neck and forelimbs into its shell for protection. The legs are large, stumpy, with dry scaly skin and hard scales. The front legs are five-clawed, and the back legs are four-clawed.

Diet: The Galápagos tortoise is a generalized herbivore feeding on grasses, vines, cactus fruit, and other vegetation. It eats the fruit of the manzanello tree and fallen fruits and spiny pads of the prickly pear.

Remarks: A slow metabolism and large internal stores of water mean they can survive up to a year without eating or drinking. Spanish sailors who discovered the archipelago in 1535 actually named it after the abundant tortoises; the Spanish word for tortoise is galápago.

California Academy of Sciences Specimen

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