Tortoises or land turtles are
land-dwelling reptiles of the family of Testudinidae, order Testudines. Like
their marine cousins, the sea turtles, tortoises are shielded from predators by
a shell. The top part of the shell is the carapace, the underside is the
plastron, and the two are connected by the bridge. The tortoise has both an
endoskeleton and an exoskeleton. Tortoises can vary in size from a few
centimeters to two meters. Tortoises tend to be diurnal animals with tendencies
to be crepuscular depending on the ambient temperatures. They are generally
reclusive animals.
It is possible, though perhaps unlikely, that among the remaining giant
tortoises of the Galápagos Islands, there exists an old-timer that was a
hatchling at the time of Charles Darwin's famous visit in 1835. Giant tortoises
are the longest-lived of all vertebrates, averaging over 100 years. The oldest
on record lived to be 152.
They are also the world's largest tortoises, with some specimens exceeding 5
feet (1.5 meters) in length and reaching 550 pounds (250 kilograms).
There are now only 11 types of giant tortoises left in the Galápagos, down
from 15 when Darwin arrived. Hunted as food by pirates, whalers, and merchantmen
during the 17th, 18th, and 19th centuries, more than 100,000 tortoises are
estimated to have been killed off. Nonnative species such as feral pigs, dogs,
cats, rats, goats, and cattle are a continuing threat to their food supply and
eggs. Today, only about 15,000 remain.
The tortoises are now listed as endangered and have been strictly protected
by the Ecuadorian government since 1970. Captive breeding efforts by the Charles
Darwin Research Station are also having positive effects.
Galápagos tortoises lead an uncomplicated life, grazing on grass, leaves, and
cactus, basking in the sun, and napping nearly 16 hours per day. A slow
metabolism and large internal stores of water mean they can survive up to a year
without eating or drinking.
Spanish sailors who discovered the archipelago in 1535 actually named it
after the abundant tortoises; the Spanish word for tortoise is galápago.
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