 Young animals emerge from the nest after four to eight months and may weigh only 50 g ( 1 @.@ 8 oz ) and measure 6 cm ( 2 @.@ 4 in ) . When the young tortoises emerge from their shells , they must dig their way to the surface , which can take several weeks , though their yolk sac can sustain them up to seven months . In particularly dry conditions , the hatchlings may die underground if they are encased by hardened soil , while flooding of the nest area can drown them . Subspecies are initially indistinguishable as they all have domed carapaces . The young stay in warmer lowland areas for their first 10 – 15 years , encountering hazards such as falling into cracks , being crushed by falling rocks , or excessive heat stress . The Galápagos hawk was formerly the sole native predator of the tortoise hatchlings ; Darwin wrote : " The young tortoises , as soon as they are hatched , fall prey in great numbers to the buzzard " . The hawk is now much rarer , but introduced feral pigs , dogs , cats , and black rats have become predators of eggs and young tortoises . The adult tortoises have no natural predators apart from humans ; Darwin noted : " The old ones seem generally to die from accidents , as from falling down precipices . At least several of the inhabitants told me , they had never found one dead without some such apparent cause " . 
