Thursday, March 12, 2009

Galapagos Giant Tortoises

I personally find Galapagos Giant tortoises most interesting. The main attraction of the island are these giant tortoises. No one knows how many giant tortoises there were originally but estimates show that there were probaly around 100.000 were hunted in total over the centuries. Persecution still continues on a much smaller scale; more than 120 tortoises have been killed by poachers since 1990. The tortoises go on a incredible journey and it is known that tortoises can float easily in sea water. Although Galapagos tortoises are classified as just one species, scientists cannot be sure whether the fourteen races they recognise actually belong to several different species.
The tortoises have very large shells made of bone. Physical features(including the shape of shell) relate to the habitat of the species. You can tell the difference between male and female as the males have a longer tail and a shorter and concave undershell, they are also larger than females. The tortoises are slow moving reptiles with an average of long distance walking speed of 0.3km/h, they can move at a surprising speed for their size. They feed on grass covered plains. In the dry season they climb back and feed on grasses of the mountain meadow.
Being cold blooded reptiles, the tortoise bask for two hours after dawn. The tortoises are herbivoroues which mean they feed on cactus,grasses,leaves,vines and fruit. Tortoises can go along time without drinking.
Mating occurs at anytime of the year, though the seasonal peaks are between January and August. The male tortoise sniffs the air when seeking a female,bellows loudly and bobs his head.Their concave shell base allows males to mount the females from behind. It brings its tail which houses the penis into the female's cloaca. After mating, the females journey up to several kilometres to reach nesting areas.The young emerge from the nest after 120-140 days. Sex can be determind only when the tortoise is 15 years of age.

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