#aldabragianttortoise

PATTERN WEEK

The Aldabra Giant Tortoise, or Aldabrachelys gigantea, only lives on the Seychelle Islands in the Indian Ocean and is known for their size with males averaging between 200-250 kilos, and females between 121-159 kilos.

They are classed as a Vulnerable species due to historic hunting practices wiping out the majority of giant tortoise species. In fact: the Aldabra Giant Tortoise is the only one of 18 giant tortoise species that has not gone extinct. The reason for the overexploitation (mainly in the 17th and 18th centuries) was that the tortoises provided an excellent source of oil and meat that could very easily be caught and could even more easily be kept on board ships (a giant tortoise can relatively easy go without food or water for an entire year!). Captive breeding programs have been able to somewhat bring the species back from the brink of dying out by releasing the captive bred tortoises back into the wild where they are now protected by conservation efforts.

What makes this effort somewhat easier is that the numbers of eggs in a clutch in captive circumstances are between 9-25 (in the wild those numbers sit between 4-14). Although in both cases only 30-50% of the eggs per clutch actually hatch, this still means that more tortoises can be released in the Seychelles.

While they have one of the longest lifespans of any animal on earth (oldest record is 255), Aldabra Giant Tortoises only reach a breeding age somewhere between 20-30 years old, making a breeding program a very slow-going and time-consuming effort. Another factor in the result of the numbers of successful hatchings is that the sex of a hatchling depends on the incubation temperature of the nest: warm eggs produce more females, cool temperatures more males. A third impact on hatchling-numbers (only happening to nests in the wild) is that eggs and juveniles are easy pickings for crabs looking for a tasty snack.