Not without cause, the Galapagos Giant Tortoise is one of the most recognizable creatures that calls the renowned Galapagos Islands home. This enormous reptile, which can weigh up to 550 pounds and live up to 150 years, is among the world’s most significant and rarest vertebrates.
Many people are unaware that these fantastic creatures formerly inhabited nearly every continent, from Asia to the Americas. However, there are currently only two groups of gigantic tortoises—the other is found in the African archipelago of Seychelles—with the Galapagos tortoise making up most of them. In the same way, the Galapagos Archipelago formerly had a quarter of a million gigantic tortoises living there.
Galapagos Giant Tortoise – Evolution and subspecies
Eleven original fourteen or fifteen species of giant tortoises called the Galapagos Islands home still exist. These groups can be broadly classified into saddleback shell and domed shell tortoises, although their sizes and shapes vary quite a bit. Those who visit the drier islands will observe that the tortoises there are smaller than those on the larger islands that receive more rainfall. Their shorter, longer limbs and saddleback carapaces, or shells, which are reverted over the rear legs and raised above the neck, can also be used to identify them. Conversely, those found on larger islands are larger and have a transparent shell shaped like a dome.
The different ecosystems provide an easy explanation for these variances. There is a great deal of cacti, for example, which bear fruit near the top of the plant, but there are also fewer flora and low-lying plants on the drier islands. Because of their elevated shells, tortoises that could extend their necks upward would, therefore, have a clear advantage over those that could not. Many subspecies across the islands have evolved to this feature, which makes it an extremely effective adaption. The saddleback shell is unnecessary in the wetter islands, where there is an abundance of lush vegetation and ground cover; in fact, it exposes the tortoise’s body to more predators.
Galapagos giant tortoise Behavior
Due to their cold blood, the giant tortoise spends most of its waking hours in the sun to stay warm. They sleep for about 16 hours a day. Moreover, they walk at a little less than 0.2 ml/hour on average. But when these creatures have a goal, they can move shockingly fast for their size. Indeed, while females are migrating to the breeding grounds, tracked individuals have been reported to go eight miles in two or three days.
Even now, the tortoises and Galapagos birds have formed a mutualistic bond so that the latter can give the former their very own bath. Small birds that are waiting to eat, such Darwin’s finches and Vermillion Flycatchers, are frequently spotted perched atop tortoises’ shells. The tortoise will extend its neck and extremities to allow the bird to feed on the ticks that are concealed in the folds of its skin, between its toes, around its head, and other areas that are otherwise inaccessible to the tortoise. The birds dance in front of the giants, signaling that they are ready to eat.
