Galápagos tortoises are the largest living tortoise — fully grown adults can tip the scales at over 650 pounds and grow to be 4 feet long. A long-lived species, this tortoise can live to be 150 years old. They are native to seven islands in the Galápagos archipelago. Though still threatened after a few centuries of over-hunting, Galápagos tortoises have been making a strong comeback in recent years thanks to the development of the Galápagos National Park and a successful captive breeding program. Unfortunately, one subspecies out of the 12 is functionally extinct — the last remaining individual lives in a zoo.