Galapagos Giant Tortoise
Image credit: © San Diego Zoo Wildlife Alliance. All rights reserved.
Describer: Quoy and Gaimard (1828) (for Testudo nigra)
Body Length: Up to 1.2-1.8 m (4-6 ft)
Appearance: Among the largest terrestrial reptiles. Long neck. Robust limbs. Bony plates on carapace and forelimbs. Jaws with sharp edges for tearing vegetation.
Carapace (upper shell): Variety of carapace shapes. Round "domed" type, flatter "saddleback" type with high anterior opening; some "intermediate" shapes also described.
Sexual Dimorphism: Males have concave plastron (lower shell). Males up to 2-3 times larger than females. Size difference particularly pronounced in saddlebacked species.
|Distribution & Status||Behavior & Ecology|
Range: Galápagos Islands, west of Ecuador.
Habitat: Found in diverse habitats.
IUCN Status: All species at risk of extinction. See each species' risk level in Conservation Status.
CITES Status: Appendix I
Population in Wild: Approximately 20-25,000 individuals
Locomotion: Slow walk, but may move substantial distances. Float well, but swim with difficulty.
Activity Cycle: Most active during the day, but spend up to 16 hours resting. Spend active time foraging and walking between habitat areas. Immobile at night and exhibit sleep-like behaviors.
Diet: Plants and fruits—grasses, shrubs, Opuntia cactus. Can go months without food or water (generate water internally by metabolizing stored fat). Drink large amounts of water, if available.
|Reproduction & Development||Species Highlights|
Sexual Maturity: typically, about 20-25 years of age
Egg description: Spherical, white; 110-120 g (3.9-4.2 oz)
Incubation: Varies depending on species and seasonal temperatures; 80-175 days
Number of clutches: 1-4 per breeding season
Nesting season: June-December
Hatching season: December-April
Longevity: estimates vary
San Diego Zoo Wildlife Alliance
© 2017-2019 San Diego Zoo Wildlife Alliance. CITES information updated Jul 2019.
Abbreviations: GGT(s) is used as an abbreviation for Giant Galápagos Tortoise(s), throughout.
How to cite: Galapagos Tortoises (Chelonoidis spp.) Fact Sheet. c2017. San Diego (CA): San Diego Zoo Wildlife Alliance; [accessed YYYY Mmm dd]. http://ielc.libguides.com/sdzg/factsheets/ galapagostortoises.
(note: replace YYYY Mmm dd with date accessed, e.g., 2017 Jan 15)
Disclaimer: Although San Diego Zoo Wildlife Alliance makes every attempt to provide accurate information, some of the facts provided may become outdated or replaced by new research findings. Questions and comments may be addressed to firstname.lastname@example.org.
Thank you to Kim Lovich, Curator of Herpetology & Ichthyology for San Diego Zoo Wildlife Alliance, for providing expert content review of this fact sheet.
Many thanks to Dr. Linda Cayot, Galapagos Conservancy's Science Advisor, for providing key information on GGT taxonomy, population estimates, nesting biology, and morphometrics.
Thank you to Jonny Carlson, Reptile Keeper at the San Diego Zoo, for providing a wealth of information on GGT husbandry practices. We appreciate his knowledge of animal care and passion for reptiles.
Dr. Elizabeth A. Hunter kindly responded to information requests regarding the biology and ecology of GGTs. Dr. Hunter conducted research on GGTs while earning her Master's degree. At the time of this writing, she is a postdoctoral researcher in ecology and conservation biology with the Department of Natural Resources and Environmental Science at the University of Nevada-Reno.
Thank you to Lisa Bissi, Photo Archive Librarian with San Diego Zoo Wildlife Alliance, for providing many of the historic photographs used in this fact sheet.