The Blue Whale
The Blue Whale (Balaenoptera musculus) is a marine mammal whose length at 30 meters (98 ft) and weight at 180 tons makes it the largest and heaviest animal ever known to have lived on earth in addition to being the longest survived animal on earth. Its long slender body is bluish grey dorsally and lighter underneath. They usually travel alone or in pairs and occasionally seen in small groups. Their main source of food is krill, a tiny shrimp like creature which they filter from the water using their fringed plates attached on the upper jaw.