The blue whale is the largest animal to ever have existed, reaching lengths of up to 100 feet and weighing as much as 200 tons. Found in oceans around the world, blue whales are baleen whales that primarily feed on krill, consuming several tons daily. Their long, streamlined bodies are a mottled blue-gray, and they have small dorsal fins located near their tails. Blue whales are known for their deep, low-frequency vocalizations, which can be heard over vast distances underwater. Despite their enormous size, blue whales are gentle creatures. They face threats from ship strikes, entanglements, and climate change, though conservation efforts are underway.