Humpback Whale

Danielle M. Williams
Life Science M @ 4:00
November 9, 1998

To look up into the mountains and see the steam rolling from a mountain stream
on a cold winters morning is a beautiful sight. However, to look out over the horizon and
see the white spray of salt water coming from the blow of a huge humpback whale is
much more exciting sight and a whole lot warmer. in the ocean, the color of the water, and
The hump-back whale gets itís name from the distinctive hump in front of the
dorsal fin and from the way it raises itís back high above water before diving.
They are a member of the order Cetacean. This order is of aquatic mammals and the humpback belongs to the suborder of the Mysticeti. The Mysticeti are the baleen whales, which have three families and several species. The family in which the humpback belongs is the Balaenopteridae; the true fin backed whale. The thing that separates this genus from the
other fin-backed whales is the pectoral fins, which grow in lengths of about 5 meters (16.4
feet). This Genus is called Megaptera meaning great wing (Tinker 290). There was a
controversy over the species name in the late nineteenth and early twentieth century.
In 1932, Remington Kellogg finally settled the matter with Megatera Novaeangliae
(Cousteau 84). The common English name is the hump-back whale.
The humpback whale lives in both the Atlantic and the Pacific oceans. Since we
live in the Pacific Iíll be discussing the humpbacks of the North Pacific. They migrate
from North to South. In the months of July through September they gather in the
Aleutian Islands, Bering Sea or the Chukchi Sea. They head south for the winter.
They go to one of three areas: (1) Between the Bonin Islands, the Marinas Islands, the
Ryukyu Islands and Taiwan; (2) The Hawaiian Islands, and (3) Along the coast of
Mexico (Tinker 291).

One of the reasons these whales go North is for feeding. They have a short food
chain compared to most mammals. Phytoplankton turns sunlight into energy and this
energy is consumed by zooplankton. The zooplankton and phytoplankton are eaten
by small fish. The whale in turn eats the fish. The chain is complete when waste products or
dead whales decompose. They have a very short time frame in which they eat compared
to the twelve months out of the year. They have not been seen feeding in Hawaii. It
seems that they only feed during the summer months up north. During the fasting
periods, in Hawaii, they survive on their blubber. They mix their diet with copepods,
euphausiids (krill), and small fish, primarily herring and capelin. They are considered filter feeders, using baleen plates to filter out their food. They take huge amounts of water into their
mouth using a gulping method and then when they push the water out, they put their
tongue up so the water must pass through the baleen. The food becomes trapped
and falls toward the rear of the mouth. The two gulping methods humpback whales use
are lunge feeding and bubble net feeding. Lunge feeding is used when food is abundant.
The whale simply swims through the prey with itís mouth open engulfing the prey. They
can do this vertically, laterally or inverted. This is done toward the surface of the ocean.
Bubble net feeding is used when the prey is less abundant. The whale dives below
the prey and discharges bubbles from its blowhole. As the bubbles ascend they form a
net that disorients the prey. Then the whale swims upward and fills his mouth with the net
of fish and bubbles (Kaufman 55). Humpbacks have ventral grooves in their throat that
expand allowing an enormous amount of water to be gulped. Humpbacks consume
nearly a ton of food in a dayís time during their feeding season.

The humpback whaleís stomach consists of three chambers and the duodenal
Ampoules much like cows. The three stomachs are separate from each other. They
have small and large intestines, a rectum, caecum and an anus. These organs are very
similar and work much the same as in most mammals. The digestive glands of a whale are
somewhat different. They do not have salivary glands that are functional. The liver is
bilobed and the gall bladder is absent. The pancreas however resembles that of most
other mammals