There are records of individuals over 100 feet, but 70-90 feet is probably average. 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. Blue whales are rorqual whales, a family of baleen whales with pleated throat grooves that expand when the animal takes in water while feeding. More than 55-68 throat grooves extend from the throat to the navel. The favorite food of these giants is krill, or shrimp-like euphasiids, that are up to three inches long. Blues must eat one to two tons of krill a day during the feeding season.