Whale watching in the world’s largest blue whale colony is one of the most exciting things to do in Unawatuna on your holidays. Mirissa is the best place to start whale watching tour in Sri Lanka. Whales, like humans, are warm-blooded mammals and breathe air despite living in water. These gigantic mammals roam throughout the world’s oceans. Among the existing Whale species, Blue Whales are the largest animals ever known to have lived on Earth. They grow up to 100 feet long and upwards, whilst their tongue weighing as much as an elephant. Whales usually swim alone or in pairs.