Skip to main content
sdzglibrarybanner San Diego Zoo Global Library

Galapagos Giant Tortoises (Chelonoidis spp.) Fact Sheet: Distribution & Habitat

Historic Distribution

Galápagos Giant Tortoises

  • 1600s-early 1800s
    • Abundant on the Galápagos Islands (MacFarland et al. 1974)
    • Estimates of up to 300,000 tortoises (Linda Cayot citing James Gibbs' unpublished data, personal communication, 2016)
  • Once found on at least nine Galápagos Islands (Edwards et al. 2014)
    • Human-caused extinctions on a few islands
      • Some human-mediated reintroductions beginning in 2010s (Cayot 2015a)

Giant tortoises (all species)

  • Once widespread on all continents, except Antarctica (Powell and Caccone 2006; Hansen et al. 2010; Blake et al. 2015a)
    • Until the late Pleistocene, < 1.8 mya
  • “…extant giant tortoises are not island oddities, but rather the last examples of a once widespread lineage” (Blake et al. 2015a)
  • Once common on islands in the Indian and Pacific Oceans (McDougal 2000; Standford 2010; Blake et al. 2015a)
    • Overhunting by humans was main driver of their extinction
    • Only surviving giant tortoises
      • Galápagos and Aldrabra Giant Tortoises (near Seychelles, Indian Ocean)
        • Not particularly closely related (Powell and Caccone 2006)
        • Independently evolved gigantism (Powell and Caccone 2006)

Current Distribution

Galápagos Giant Tortoises (GGTs)

  • Approximately 20-25,000 GGTs in the wild (Cayot 2015a; galapagos.org)
  • Recent reintroductions to islands where GGTs were driven to extinction (Cayot 2015a)
    • Now, about 9-10 islands with GGTs
  • Most major islands with a single GGT species (Poulakakis et al. 2012)
    • Isabela and Santa Cruz have more than one species
  • Elevation range
    • Adults: 0-429 m (0-1,407 ft) (Blake et al. 2015a)
    • Juveniles remain in lowlands; not found at high elevations (Blake et al. 2013)

The Galápagos Islands

(Poulakakis et al. 2012; Blake et al. 2015a; UNESCO.org  c1992-2016, except as noted)

  • Chain of volcanic, oceanic islands
    • Never been connected to mainland South America
  • 960 km (597 mi) west of Ecuador
  • 129 islands, islets, and rocks
    • Official names for 13 large (over 1 km2) islands, 6 smaller islands, and over 40 islets
  • Approximately 8,000 km2 (3,088 mi2) of land over 45,000 km2 (17,375 mi2) of ocean
  • Volcanic activity is ongoing (Caccone et al. 1999)
  • Climate
    • Hot, wet season: January to May
    • Cool and dry the rest of the year
  • Oldest islands
    • San Cristóbal: emerged ~4 mya
    • Española: emerged ~3.5 mya
  • Younger islands to the west
    • Youngest island: Fernandina
      • Began forming less than 70,000 years ago
  • Four islands inhabited by humans (National Census of Ecuador, 2010; Orenstein 2012)
    • Human population: 25,000-30,000
    • Santa Cruz
    • San Cristóbal
    • Isabela
    • Floreana
  • 1535: First record of humans visiting the islands
    • Fray Tomás de Berlanga, Bishop of Panama, names the islands “Galápagos”
      • From galapagos (Bonin et al. 2006)
        • Old Spanish word for chelonians (turtles and tortoises)
  • 1959: Terrestrial areas declared a National Park
  • 1978: Named a UNESCO World Heritage Site
  • 1986: Galápagos Marine Reserve created
  • Also see History

Habitat

  • Varies with species
  • Humid uplands (Bastille-Rousseau et al. 2016)
    • Lots of grass and vegetation
  • Moist, volcanic craters (Bonin et al. 2006)
  • Arid lowlands (Bastille-Rousseau et al. 2016)
  • Dry, grassy or dry, rocky areas (Bonin et al. 2006)
  • GGTs prefer areas of high cactus density, where cactus is available (Gibbs et al. 2014)
    • Avoid woody plants, which limit movements

Distribution Map

Galapagos Tortoise distribution map

Giant Galápagos tortoise distribution.

Adapted from www.d-maps.com.
Click here or on map for detailed distribution from Wikipedia.

SDZG Library Links