ar nubbin to a
more substantial, sharply falcate fin. The dorsal fin frequently
includes a step or hump, which is quite distinct when the animal arches
its back to begin a dive and from which the species derives its common
name.

Humpback whales are basically black in color with a white region of
varying size on the belly, which upon close examination may often be
seen to be crosshatched with thin dark lines; the flippers and the
undersides of the flukes also are white.

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 o