Hammerhead sharks are fearsome looking beasts that patrol the waters in which they live as if they have no fear of anything in the ocean. It's not surprising that they are so confident considering the fact that they have highly evolved vision and sensory organs that make them especially capable hunters. Unlike most shark species, hammerheads school in groups of more than 100 individuals by day, although they are solitary at night when they are hunting. Often seen in large congregations in areas such as this one, in the Galapagos Islands, they drift slowly on the current. This is a magnificent sight to see and scuba divers come from all over the world to swim among these awe inspiring animals. Always in motion, most species of shark lack a swim bladder and they must constantly move to stay off the bottom. They are also able to breathe more easily as the movement causes greater water flow over their gills. Hammerheads are actually able to rest one hemisphere of their brain in a sleep-like state while the other hemisphere remains active to watch for threats. These hammerheads occasionally ventured close to the divers to investigate the strange and clumsy creatures that were perched on the rocks watching them with even greater interest. For scuba divers, seeing a wall of hammerheads cruising past them can only be described as the world's largest and most spectacular Imax theater experience. The Galapagos Islands are roughly 4 million years old. This is very young in geological terms. The islands formed through the eruptions of underwater volcanoes that shot pillars of lave and cooling rock towards the surface. These rocks eventually became home to plants and then birds, lizards, reptiles and other creatures that made their way through the air or on the ocean's currents. The currents have also brought an abundance of marine life as well. Three major currents converge here and create an upwelling of nutrients and food that brought small fish. Larger fish and animals that feed on those fish thrive here. This is one of the most diverse and fascinating areas of the planet. For nature enthusiasts and underwater adventurers alike, the Galapagos Islands represent one of the most thrilling worlds to explore.