The giant tortoise sleeps for about sixteen hours each day and keeps cool either by taking mudbaths or by partly submerging itself in water. They can survive for long periods without drinking and obtain most of their moisture from the dew found on vegetation. Fresh young grass is the favourite food of the tortoise but in the drier regions of the Galapagos Islands this is often scarce so instead they feed on the Opuntia cactus.
Between the Galapagos tortoise and the finch there has evolved a special relationship. The finches like to eat the ticks and parasites from the tortoise's skin and the tortoise seems only too happy to let them do this. The finch hops in front of the tortoise to show that it is ready and the tortoise then raises itself up high on its legs and stretches out its neck so that the bird can reach the parasites.Read More: Breeding