The Galapagos Giant Tortoise is the world's largest tortoise. It is native to several islands of the Galapagos group off Ecuador (the islands named after a Spanish word for terrapin).
Populations have been decimated by sailors capturing them for long-storage meat supplies and by introduced feral goats, pigs, dogs and rats eating their herbage or young.
There are several subspecies of Galapagos Giant Tortoise (sometimes called races/clades or even full species) in different habitats on the same and different islands.
Subspecies differ particularly in size, shell shape and neck length for grazing or reaching higher vegetation.
Unfortunately, it took Darwin a long time to recognise the evolution of the different sub- or full species and it took zoologists even longer.
Since these giants can live some 200 years and, through ignorance, were not segregated by (sub) species, most of those in captivity are hybrids.
Lonesome George, the last of the Pinta Island (Abingdon) subspecies, received publicity when he passed away in 2012.
There are breeding programmes for most of the remaining pure-bred species, to bolster remaining wild populations. (Captive collections also continue to breed hybrids.)
Illustration of different carapace (shell) shapes: some widely-domed, as centre left, and some narrow-topped like a saddle, as centre right.
Others have a high arch in the front collar area so the tortoise can eat high shrubs.