Page 71 - Reptiles & Dinosaurs (Britannica Illustrated Science Library)

66 TURTLES AND SNAKES REPTILES AND DINOSAURS 67

Long-Lived Giants Almost 1,000 eggs Giants

There are now 11 subspecies of Galapagos tortoises, including
CAN BE LAID BY A FEMALE IN ONE SEASON. HOWEVER,
iant tortoises once lived on all the continents except Australia and Antarctica, both VERY FEW YOUNG TORTOISES SURVIVE. water-dwelling and land-dwelling varieties. All are in danger of
extinction. They differ in maximum sizes, shell shapes, and neck
before and during the Pleistocene Era. They are now extinct on the continents and lengths.
G are only found on the Aldabra atoll in the Seychelles islands in the Indian Ocean Human 6 feet
(1.8 m)
and on the Galapagos Islands off the coast of Ecuador. In the Galapagos there are Tortoise 4 feet
(1.2 m)
distinct populations living in different parts of its small area. The Galapagos giant Chaco
tortoise, Geochelone nigra, is the largest tortoise in the world, weighing up to 880 HUMPED BACK Tortoise 0.8
enables it to
pounds (400 kg). The oldest one still living is over 175 years old. stretch its neck foot (0.25 m)
upward.
CLOSE RELATIVES
The Chaco tortoise
LONESOME GEORGE (Geochelone chilensis) is a
Pinta is the nickname of the RETRACTABLE NECK SHELL continental ancestor.
(home of enables it to hide its weighs over 550
Roca Redonda “Lonesome Genovesa only survivor of a now head inside its shell. pounds (250 kg),
George”) extinct subspecies
Marchena enough to crush
Equator 0° (G. nigra abindoni). Almost
a human.
Santiago
Bartolomé
GALAPAGOS GIANT TORTOISE Seymour 14 months
Geochelone elephantopus Baltra
Rábida LONG NECK THE LENGTH OF TIME A TORTOISE CAN
Habitat Galapagos Islands Fernandina San Cristóbal LIVE WITHOUT EATING OR DRINKING
Santa Cruz can reach the
Diet Herbivorous Pinzón leaves of
Height Up to 47 inches (120 cm) Santa Fe bushes. PLATES
are pointed, in
Length Up to 59 inches (150 cm) GALAPA GOS I SLANDS
Isabela the case of
Asian tortoises.
Española
Floreana
1
Reproduction
Mating BRIDGE
is rather aggressive; the joins the upper
male immobilizes the shell to the
female in order to mount FRONT LEGS plastron.
and fertilize her. are useful for
The Life Cycle 5 climbing. Main Predators
Up to four months can pass between the time a
new turtle is conceived and the time it hatches. 40 Years In addition to suffering from poaching humans in the
Laying eggs takes several hours of work, and a Most Stable past, Galapagos tortoises are in danger of extinction
female can lose up to 20 percent of her weight Size because of the low survival rate of their hatchlings, which
during this process. The large size of Galapagos After this point, its rate are hunted by two types of species that have been
2 tortoises makes them lazy; they spend most of of growth slows. introduced to their habitat: black rats and cats. Furthermore,
their time sunning themselves in small groups on SCALES the diet of adult female tortoises causes them to compete
warm, dry volcanic soils near the coast or a for food with goats and other livestock, more species not
One to Two Months Later swamp. Some eat carrion. are typical of native to the tortoises' ecosystem.
Egg Laying Nesting this order of
reptiles.
During the reproductive season, For nearly five hours, the female ANIMALS INTRODUCED
BY HUMANS
the female lays eggs every two 3 digs a funnel-shaped hole with her
weeks and makes from three to claws, softening the ground with
eight nests. Two Months Later her urine. She settles the eggs in
Hatching 4 layers, covers them with earth, and RATS GOATS
smoothes it down.
After hatching, the young
2.5 inches (6 cm) climb to the surface, Five Years
usually at night. CLAWS
Development are used for
The animal reaches digging.
Giant Egg reproductive age, although
Its shell is hard it will keep growing
and spherical. throughout its life.
DOGS HOGS