Black and white illustration of a blue whale on a white background.
The Blue Whale, at approximately 100 feet in length and 200 tons, is the largest known animal ever to have lived on Earth. A blue whale’s tongue alone is larger than an elephant; its heart is larger than an average-sized car. Despite their large size, blue whales are not aggressive predators. Rather, they subsist on a diet of almost solely krill—tiny shrimp-like animals. Blue whales usually swim alone or in pairs, and can be found in all the oceans around the world. In addition to owning the title of largest animal, blue whales are also considered the loudest animals on earth. Like other whales and dolphins, blue whales use groans and pulses to both navigate and communicate.
Blue whales have few natural predators, however they were driven to near extinction by the mid-20th century due to aggressive hunting. They became a protected species in 1966, and though populations have grown to some extent since then, as of 2015, the blue whale is still officially classified as an endangered species. It is thought that there are between 10,000 to 25,000 of these gentle giants currently living in the wild.