It is scarcely possible to imagine the size of the blue whale, the largest animal inhabiting the earth. Its heart alone is as large as a small car. Blue whales are an overall blue-gray color, mottled with light gray. Blue whales are long and streamlined. The dorsal fin is extremely small, and the pectoral flippers are long and thin.
Blue whales swim individually or in small groups.
Pairs are very commonly seen. Approximately 2,000 blue whales live off the waters of California and Mexico. Blue whales are rorqual whales, a family of baleen whales with pleated throat grooves that expand when the animal takes in water while feeding. In blue whales, 55-68 throat grooves extend from the throat to the navel. The favorite food of these giants is krill, or shrimp-like euphausiids, that are up to three inches long.