Real-life sirens of the sea, humpback whales boast some of the longest and most rhythmically diverse songs in the animal kingdom, surpassing the vocal ranges of any other whale in haunting performances that can be heard 20 miles away. (“Vocal” is a term of art; the sound is created by forcing air through the nasal cavities.) All the males within the same general area sing slight variations of the same song, which evolves over time. Acrobatic crowdpleasers, humpback whales are famous for breaching, or jumping up out of the water using their powerful tail flukes. They also slap the water with their fins and flukes. Whether all this is to show off, stun prey, dislodge barnacles or just have fun is up for debate.
Reaching 50 to 60 feet in length, humpbacks weigh up to 40 tons and are dark gray with varying white patterns on their fins, belly and flukes (researchers use fluke markings for identification). Their pectoral fins can reach 15 feet in length. Naturally, humpbacks also have a hump—the fat stored beneath the dorsal fin gives the whale its common name. Individuals live for at least 50 years, and some may survive up to 80 years. The females are larger than the males.
Humpbacks, like other whales and like dolphins, sleep by resting one half of the brain at a time; they must do this because they are "voluntary" breathers (unlike us humans, for example, who breathe reflexively) and need to take regular breaths.
Quite the cosmopolitan species, humpbacks range throughout the world’s oceans in about a dozen general populations. Humpbacks migrate in small pods of two to three from winter breeding grounds near the tropics to summer hunting grounds near the poles or other cold-water destinations. During migration, protective mothers stay close to their calves, often touching fins.
Instead of teeth, humpbacks have up to 400 pairs of fingernail-like baleen that filter krill and small school fish out of the water. Humpbacks are ingenious herders that create “bubble nets” to corral fish. Each whale can eat up to a ton of food a day in the summer. They eat almost exclusively during the summer.
Once hunted almost to extinction, humpbacks now number about 80,000 worldwide and in 2008 were named a species of “least concern” by the IUCN. They are still considered endangered by the U.S. government, though federal agencies are considering listing populations separately, as some groups—for example, those in the North Pacific seen in Hawaii and off the coast of California—are faring pretty well.
—L. Clark Tate