Natural History Notes
The blow of humpback whales is from 8 to 10 feet (2.4 to 3.1 m) tall and has been described as balloon-shaped. It is wide relative to its height. Feeding humpback whales habitually blow 4-8 times at intervals of 15-30 s after a long dive. In the tropics they habitually blow 2-4 times in succession when beginning a long dive. In diving, humpback whales throw the tail flukes high into the air, exposing the sometimes white undersurface and the rippled rear margin.
Humpback whales often leap clear of the water, raise a flipper, and slap it against the water, or "lobtail," raising the tail high into the air and bringing it crashing back to the water in a loud report. Often, particularly when they are encountered on their tropical breeding grounds, humpback whales will be found lying on their sides with a long flipper in the air.
Humpback whales feed on krill and schooling fish.
May Be Confused With
From a distance humpback whales may be confused with any of the other large balaenopterid (rorqual) whales—blue, fin, sei, or Bryde's. Although it is highly variable, the dorsal fin most closely resembles that of the blue whale. However, it is located farther forward on the back. Humpback whales distinguish themselves from the remainder of the rorquals by their habit of raising the flukes high into the air when starting a long dive. (In very shallow water they may not raise the flukes at all.) The only other rorqual to do so—the blue whale—raises the flukes slightly or not at all.
Under some conditions humpback whales may be confused with sperm whales at a distance. When arching the back to begin a dive, both may show a distinct hump. Both species frequently raise their flukes nearly vertically when beginning a long dive but differ in several ways. The flukes of humpback whales show varying amounts of white beneath, are pointed on the tips, and are distinctly concaved and irregularly rippled on the rear margin. Those of sperm whales are all dark and more flattened and even along the rear margin. Further the species can be distinguished in the following ways:
| Humpback Whale | Sperm Whale |
|---|---|
| BLOW | |
| Projects upwards from centerof head. Usually blows4-8 times (2-4 times intropics) before diving. | Projects obliquely forwardfrom left side of snout.Usually blows many times(20-50 or more) before diving. |
| HEAD | |
| Raised area around blowholes,knobs on upper surface. | Blunted, long, smooth. |
| FLUKES | |
| Often white underneath,concaved and scalloped onrear margin, deeply notched. | Smooth, all black on rearmargin. |
| FLIPPERS | |
| Extremely long (to one-thirdof body), white and scallopedon leading edge. | Short; all black. |
| DORSAL FIN (OR HUMP) | |
| Triangular to falcate fin,including a step or hump infront of the dorsal fin;smooth. | Rounded hump, two-thirdsback on back followed byknuckles or crenulations. |
When they can be examined at close range, humpback whales can be easily distinguished from all other large whale species with a dorsal fin by the tuberosities or knobs on the head, by the long white flippers scalloped on the leading edge, by the small distinctive dorsal fin, and by their distinctive tail flukes.