An wild old giant tortoise eats grass in the Galápagos Islands on Santa Cruz Island

galapagos tortoise galapagos islands western santa cruz tortoise giant tortoise santa cruz santa cruz island chelonoidis niger porteri herbivore shell old ancient vulnerable endemic graze grazing tortoiseshell reptile reptilian reptiles land tortoises darwin charles darwin ecuador native species tortoise shell lonesome george biodiversity conservation isla santa cruz wild extinct terrestrial eating shells charles darwin research station galapagos national park national park galapagos giant tortoises tortoises chewing herbivorous slow chelonoidis gianttortoise tortuga chelonoidis porteri