KILLER WHALES: The killer whale, or orca, is a formidable predator in its own right, but when banded together with others it is practically unstoppable. The orca uses echolocation to find its prey, emitting a series of clicks that bounce off objects and are received by a bone in the jaw. This transmits the information to the brain, which forms a three-dimensional picture of what lies ahead, allowing the orca to hone in on its prey. Orcas are among the fastest animals in the sea, and at up to seven tons in weight, they are among the largest predators on earth. Combine this with supreme intelligence and highly-coordinated hunting skills, and a pod of orcas is like an underwater legion of elite warriors.