Whales are one of the world's most powerful predators. Whales are endothermic (commonly called warm-blooded). When it comes to senses, hearing is the most important one to whales. They use echolocation to communicate and hunt. They are known to grab seals right off the ice. They also eat fish, squid, and seabirds. he largest whale (and ever existing animal) is the blue whale: up to 33 m (100 ft) in length.