Giant Galapagos Tortoise happily munches away on grass

Giant Galapagos Tortoises are one of the most recognizable animal species on earth. Their enormous size and their slowness, along with their extremely gentle disposition make them a very endearing creature. They are also very vulnerable because they move in slow motion and would have no hope of escape. Their only defense is to retreat into their shells and patiently wait for predators to become bored or too hungry to wait for them to emerge. These Galapagos Tortoises are believed to be capable of reaching 200 years of age. They can weigh over 227kg (500lb) and reach a size that would fill the passenger compartment of a compact car. They can go a year or more without food or water so it's no wonder that retreating into their shell is a successful means of avoiding being eaten. The people of the Galapagos have worked very hard to help these tortoises rebound from near extinction. They have sanctuaries and captive breeding programs to ensure the survival of the species, and they have strict laws about protecting them from interference from humans. In fact, the people of the Galapagos Islands understand better than anyone how important it is to allow nature to look after its own creatures. They respect the delicate balance and they also appreciate the need to reduce the impact of humans on habitat and the natural behaviour of the wildlife. This fully grown tortoise happily munches away on some grass and other vegetation outside one of the sanctuaries on San Cristobal Island. Possibly as old as 200 years, he might have been on this expanse of land back when Charles Darwin made his legendary voyage on the HMS Beagle in 1835 that brought him to these islands and led him to publish his theories of evolution. Darwin's understanding of the unique adaptations of the animals here taught him a great deal about evolution. It was these theories that changed the way we looked at history, at our planet, and even at ourselves. The tortoises of the Galapagos have evolved to have higher and deeper indentations in their carapace (shell) that allow their necks to extend higher. This allows them to reach vegetation growing higher off the ground. This adaptation is crucial to survival on these islands where water is scarce and vegetation is hard to find during dry seasons.