Galápagos tortoiseChelonoidis niger — habitat, diet and reproduction

Head of a grey-skinned giant Galápagos tortoise chewing green leaves

Galápagos tortoise (Chelonoidis) eating plants. · Charles J. Sharp / CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0). Cropped and resized.

The Galápagos tortoise is the largest land tortoise in the world. Big males can weigh over 400 kilograms, and some individuals have lived more than a hundred years. It lives only on the Galápagos Islands in the Pacific Ocean, where it inspired Charles Darwin’s observations.

Quick facts

Common name	Galápagos tortoise, giant tortoise
Scientific name	Chelonoidis niger (species complex)
Lifespan	Over 100 years
Length	Shells of large males reach about 1.5 m
Weight	Large males can exceed 400 kg
Diet	Herbivore: grasses, leaves, cacti, fruit
Predators	Adults have no natural predators; introduced animals eat eggs and young
Conservation status	Species assessed from Vulnerable (VU) to Critically Endangered (CR)
Distribution	Only the Galápagos Islands (Ecuador)
Habitat	Dry cactus lowlands and moist, grassy highlands
Family	Testudinidae
Reproduction	Lays eggs in nests dug in soil

Primary category:Reptiles
Explore this animal's categories:
Animals of South America Egg-laying animals G Herbivores Reptiles Shelled animals Slow animals Threatened animals Vertebrates Wild animals

Interesting facts

Several species of giant tortoise live on the islands, each on its own island or volcano.
Some have domed shells; others have a raised “saddle” at the front that lets them stretch up to cacti.
They can survive months without food or water, so sailors kept them alive on ships.
Lonesome George, the last tortoise from Pinta Island, died in 2012.

Characteristics

Giant tortoises have a large, heavy shell, thick elephant-like legs and a long neck. The skin is grey and scaly.

Shell shape varies by island. On large, wet islands with low grass, shells are domed. On dry islands where food grows higher, the front of the shell rises like a saddle. Males are much larger than females.

Behaviour

Tortoises are slow and rest for many hours, especially early in the morning and in the heat. They wallow in pools and mud, which cool them and protect them from mosquitoes.

Some populations migrate seasonally, climbing to moist highlands in the dry season and returning to lowlands in the rainy season, along paths used for generations.

Habitat and distribution

Giant tortoises live only on some of the Galápagos Islands, about 1,000 km off the coast of Ecuador.

Some species live in arid cactus lowlands, others in moist forests and grasslands on volcanoes. Each species developed in isolation on its island.

Diet and feeding

They are herbivores, eating grasses, leaves, flowers, fruit and fungi. Prickly pear cacti are important because they also provide water.

They can store water and survive long periods without drinking. By feeding and moving, tortoises spread seeds and shape island vegetation.

Reproduction and life cycle

Mating takes place mainly in the hot, wet season. Females travel to lowlands, dig a hole with their hind legs and usually lay 2–16 round eggs the size of tennis balls.

Eggs develop for months in the warm soil, and temperature determines the sex of the young. Hatchlings dig out alone and grow very slowly, maturing at 20–25 years.

Name and history

The islands’ name comes from an old Spanish word, “galápago”, used for a tortoise or a kind of saddle, so the islands were essentially named after these tortoises.

In 1835, Charles Darwin visited and learned that locals could tell which island a tortoise came from by its shell. Such observations helped him develop his theory of evolution.

Conservation and threats

Between the seventeenth and nineteenth centuries, whalers and pirates removed tens or even hundreds of thousands of tortoises for meat. Goats, pigs and rats brought by people destroyed vegetation, eggs and young, and some species vanished completely.

Today, Galápagos National Park and conservation groups breed young tortoises and remove invasive animals. On Española Island, the population grew from 14 adults to more than a thousand tortoises.