galapagos giant tortoise

100 150 2-1 4-5 400 900 adaptations archipelago beak-like biodiversity bodies brown cacti charles conservation dark darwin diet dome-shaped ecosystem ecuador endangered endemic environmental evolution eyes feet galápagos giant grass grayish-black habitat head heavy herbivore herbivorous impact islands land largest leaves legs long longevity massive metabolism meters mouth movements mph national necks parks populations pounds predators protection reptile shell slow slow-moving small soulful species sturdy theory thick tortoise tortoises unique variations vegetation years