The species known as the Sperm Whale is possibly one of the better known whale species alongside the Blue Whale. The Sperm Whale, in fact, holds the distinction of having the largest brain of all animals on earth. The brain of a Sperm Whale is also believed to be five times heavier than the human brain. This whale species is large toothed and is also the largest predator with teeth. It can grow for an average of sixteen meters in length and is fairly large in comparison to most whale species. Sperm Whales have a life span of around sixty years and are also able to dive deep into the waters in order to feed. Sperm Whales mostly live on a diet comprised of squid. For those who wish to see Sperm Whales, the Southern coast of Sri Lanka is ideal between December and April. Indeed, whale watching is listed as one of the things to do in Kalutara, a town on the coastal belt of the island.