Iguana Cove Tortoise
A population of roughly 2,575 Iguana Cove tortoises can be found at the southwestern tip of Isabella Island at the foot of the 1,640 meter (5,380 ft) high Cerro Azul volcano. Exposure to whalers and sealers over the past several centuries took a terrible toll on the Iguana Cove tortoises and human predation continued into the 1960s due to cattle companies established in the area.
(image via: Tartarugas)
Now that pressure from feral cats, dogs, pigs and black rats has been reduced by concerted human intervention, the Iguana Cove tortoise (Chelonoidis nigra vicina) is enjoying a population rebound though IUCN still lists the subspecies as Endangered.
James Island Tortoise
The officially Endangered (by IUCN) James Island tortoise (Chelonoidis nigra darwini) roams the central to western regions of Santiago Island where it remains under intense pressure by feral pigs (who dig up its nests) and goats (who destroy coastline vegetation). The estimated population of 1,165 is heavily tilted in favor of males though efforts by the Charles Darwin Research Station are assisting the subspecies in rebuilding its formerly abundant population.
(image via: Insect Images)
Charles Darwin may have laid the foundation for modern evolutionary theories but he was very much a man of his times in other ways. In describing this particular subspecies in 1845 and comparing it to other giant tortoises, he wrote “the tortoises from James Island are rounder, blacker, and have a better taste when cooked.”
Sierra Negra Tortoise
Considered to be Endangered by IUCN, the Sierra Negra tortoise (Chelonoidis nigra guentheri) numbers around 700 individuals making up two separate populations on the eastern and west to southwestern slopes of Isabella Island’s 1,124 meter (3,687 ft) high Sierra Negra Volcano. Once numerous, Sierra Negra tortoises were extensively exploited for their oil well into the 1950s.
(image via: UMD)
The Galápagos Islands are volcanic in origin and eruptions are not uncommon – the threat of an eruption from the Sierra Negra Volcano in 1998 prompted biologists to bring 20 tortoises into captivity where they could breed in relative peace. Though the numbers of this subspecies remain dangerously low, limited reproductive success in the wild plus the ongoing captive breeding program should keep Sierra Negra tortoises viable for some time to come.
Hood Island Tortoise
As the only Galápagos giant tortoise designated “Critically Endangered” by IUCN, the Hood Island tortoise (Chelonoidis nigra hoodensis) is enjoying a resurgence from the edge of extinction via the helping hands of the Charles Darwin Research Station. Only 2 males and 11 females could be found when the project began; they were joined by a third male fortuitously found at the San Diego Zoo. The research station’s captive breeding program has managed to multiply the original 13 tortoises to over 1,000 youngsters now roaming their ancestor’s original habitat on Española Island.
(image via: Arkive)
Hood Island tortoises are one of the smallest giant tortoise subspecies, possibly as a function of Island Dwarfism on isolated, 60 square kilometers (23 sq mi) Española Island. Environmental pressures have encouraged the tortoises to evolve long limbs, extended necks and arched carapace openings that allow the tortoises to exploit vegetation growing higher than most other subspecies can reach.
Duncan Island Tortoise
Native to the southwestern region of tiny (18 sq km or 6.95 sq mi) Pinzón Island, this particular subspecies of giant tortoise resembles the Hood Island tortoise with its long legs & neck and its saddle-shaped shell. Duncan Island tortoises (Chelonoidis nigra duncanensis) are small, as giant tortoises go, and their shells show exaggerated scalloping and a saddle-style shape.
(image via: Arkive)
IUCN lists the Duncan Island tortoise as EW – “Extinct in the Wild”, though captive breeding programs have boosted the overall population to over 500 and most captive-bred youngsters released into the wild between 1970 and 1990 have survived.
(image via: Huffington Post)
“Lonesome George” was an Abingdon Island tortoise (Chelonoidis nigra abingdoni) who was discovered living in isolation on Pinta Island in 1971. Taken into captivity for his own protection and to facilitate attempts at breeding, the estimated 100-year-old tortoise died of unknown causes on June 24th of 2012 and was found by his human caretaker of 40 years, Fausto Llerena (above, with George). Though George wasn’t able to perpetuate his subspecies into the future, his long and lonely vigil generated a significant amount of interest worldwide in giant tortoises: not a father perhaps, but a Godfather certainly!