Main Characteristics: The Galapagos Tortoise is the largest living Tortoise. They reach lengths up to 1.2 m (4 ft) and they weigh over 150 kgs (330 lbs).
They have a huge carapace (shell) which is an integral part of their skeleton. When they feel threatened they can draw their head and limbs inside and the shell acts as protection.
There is a large amount of variation in the shape and size of their shell as it depends on which island the tortoise originates and the environment it has to adapt to. Those tortoises that are found on wetter islands that have an abundance of grass and vegetation near the ground have "dome shaped" shells, while those on dryer islands have a "saddle back" shell where the rim of the shell is raised above the neck allowing them to raise their head and eat from taller vegetation.
Some Galapagos Tortoises have aspects of both the above shell types and these are known to have "table top" shells. Regardless of the shell shape, all males have a concave undershell which facilitates mating.
Galapagos Tortoises with dome shaped shells tend to be the heaviest and largest of the subspecies, but they have shorter necks and smaller legs than those with saddle back shells. There is little variation in the dull brown colour of the shell or legs in any of the subspecies and in all subspecies, males are larger than females.
They have strong, toothless jaws which suit their herbivorous lifestyle and they spend most of the day grazing in small herds or basking in mud or pools.
Galapagos Tortoises are slow moving, averaging a long distance walking speed of 0.3 km/hr (0.18 mph), although if the tortoise has a purpose, for example moving to breeding grounds, they can move more quickly.
Habitat: Galapagos Tortoises are found on the Galapagos Islands. They have a regular routine that is carried out each day and they use the same sleeping place and the same pathways to get around the island.
Diet: Galapagos Tortoises are herbivores and they feed on a variety of grasses, leaves, cactus, vines and fruit. They obtain most of their moisture through their diet and can go for long periods without drinking.
Breeding: During the breeding season males become very territorial. They mate between January and March and males court females by nipping their legs and ramming their shell. Between June and December females travel several kilometres to find a suitable nest site and they dig a chamber beneath the ground, approximately 30 cms (12 inches) deep, in which to lay their eggs.
2 - 16 hard shelled eggs are laid and the female makes a muddy plug from soil, leaves and urine to cover the eggs then she leaves them to incubate. Between 100 and 200 days later the young tortoises will hatch and dig their way out of the nest. They are left to fend for themselves and mortality is high during their first few years.
The sex of the Galapagos Tortoise can be determined when they reach 15 years of age. They reach sexual maturity between 20 and 25 years old and they reach their full adult size at 40 years of age.
Predators: Historically humans have been predators of Galapagos Tortoises as they used to kill them for meat. Humans also introduced pigs, dogs, rats and goats to the Galapagos Islands which either competed with the tortoises for food or ate the eggs that they laid.
Today the tortoises are protected and there are captive breeding programmes to increase the population.
Subspecies:There are thirteen subspecies of Galapagos Tortoise:
Pinta Tortoise (Geochelone nigra abingdoni) Extinct (24th June 2012). Lonesome George is the name given to the tortoise that was thought to be the last surviving member of this subspecies. He died on 24th June 2012.
Volcán Wolf Tortoise (Geochelone nigra becki)
San Cristóbal Tortoise (Geochelone nigra chathamensis)
Santiago Tortoise (Geochelone nigra darwini)
Pinzón Tortoise (Geochelone nigra ephippium)
Fernandina Tortoise (Geochelone nigra phantastica) Extinct
Floreana Tortoise (Geochelone nigra elephantopus) Extinct
Sierra Negra Tortoise (Geochelone nigra guntheri)
Española Tortoise (Geochelone nigra hoodensis)
Volcán Darwin Tortoise (Geochelone nigra microphyes)
Santa Cruz Tortoise (Geochelone nigra nigrita)
Volcán Alcedo Tortoise (Geochelone nigra vandenburghi)
Cerro Azul Tortoise (Geochelone nigra vicina)
|Latin Name||Geochelone nigra|
|Length||Up to 1.2 m ( 4 ft)|