The largest living species of tortoise is the Galápagos tortoise (Chelonoidis nigra). Native to the Galápagos Islands, these tortoises can weigh over 400 pounds and reach lengths of up to 6 feet. They are known for their long lifespan, often living over 100 years, with some individuals reported to have lived for more than 170 years. The Galápagos tortoise has a unique shell shape that varies depending on the island they inhabit, with some possessing a saddleback shell adapted for browsing on higher vegetation. Conservation efforts are crucial to protect these iconic reptiles due to threats from habitat loss and invasive species.