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On islands with humid highlands, the tortoises are larger, with domed shells and short necks; on islands with dry lowlands, the tortoises are smaller, with "saddleback" shells and long necks. Charles Darwin's observations of these differences on the second voyage of the Beagle in 1835, contributed to the development of his theory of evolution.
Volcán Wolf tortoise. Conservation status Vulnerable [16] Rothschild 1901 [17] Reproduction is successful. Apparently two morphotypes occur on Volcán Wolf, domed and saddle-backed. A more flattened or dome-shelled population from the south may have crossed the former lava barrier and mixed with an isolated population of saddle-backed ...
It has a thick, heavy shell intermediate between saddle-backed and domed, and not appreciably narrowed anteriorly. Males are larger and more saddle-backed; females are more domed. Until eradication programs, virtually all nests and hatchlings were destroyed by black rats, pigs, dogs, and cats. [3]
They differed from any other giant tortoise species because of their modified jaws, reduced scales on the legs and shells averaging just 1mm thick. The shells of the giant tortoises were open-ended; the name Cylindraspis actually means "cylinder-shaped". This was a specific adaptation in response to the lack of predators, where thick, heavily ...
Chelonoidis niger chathamensis, commonly known as the Chatham Island giant tortoise or the San Cristóbal giant tortoise, is a subspecies of Galápagos tortoise endemic to San Cristóbal Island in the Galápagos.
Giant Galapagos Tortoises are unbelievably large animals. Fully grown, they would fill the passenger compartment of a small car. Weighing up to 227kg (500lb), they are slow moving, but very powerful.
Scientists have reported that a rare species of giant tortoise thought to have died out more than a century ago is not in fact extinct. Genetic research has shown that a female specimen discovered ...
The now-extinct West Indian radiation is thought to group with the Chaco and Galapagos tortoises but is significantly basal to both, and was a rather evolutionary distinct lineage, having diverged well before any of the modern species in the genus did and only 7 mya after the divergence of Chelonoidis from African tortoises.