The largest species of tortoise is the Galápagos tortoise. Native to the Galápagos Islands, these tortoises can weigh over 500 pounds and reach lengths of up to 4 feet. They play a vital role in their ecosystems, influencing the vegetation and helping to maintain balance on the islands. Galápagos tortoises have a long lifespan, often living over 100 years. Conservation efforts are in place to protect them due to threats such as habitat loss and invasive species.