Although Galápagos tortoises are huge animals that weigh several hundred pounds, their shells are not solid. Instead, they are made up of honeycomb structures that hold small air chambers. This makes the shell lighter and easier for the tortoise to carry.
Each of the 13 larger islands in the Galápagos Islands has a different subspeciesA subdivision of a plant or animal species that shows differences from others of the same species. For example, there is a species of animal called lion; there are two subspecies of lion, the African lion and the Asian lion. of the giant tortoise, uniquely suited for survival on that particular island’s habitatWhere an animal or plant normally lives and grows.. For example, saddle-back shells allow the tortoise to reach food found higher off the ground, like leaves on tall bushes. On desertAn area with little rain and often with hot daytime temperatures. islands, the tortoises are smaller and are able to survive on less food.
As people made homes on the Galápagos Islands, they brought animals such as rats, dogs, and cats, which eat tortoise eggs and young tortoises. This caused the number of tortoises on the islands to drop. Today, there are only about 10,000 to 15,000 tortoises living on the islands.