12.(2011·上海卷)(B)
Humpback whales
|
|
Pectoral fin
Humpback whales are sometimes called performers of
the ocean. This is because they can make impressive
movements when they dive. The name “humpback”, which
is the common name for this whale, refers to the typical
curve shape the whale’s back forms as it dives.
Sometimes the humpback will dive with a fantastic
movement known as a breach. During breaching the whale
uses its powerful tail flukes to lift nearly two-thirds of its
body out of the water in a giant leap. A breach might also
include a sideways twist with fins stretched out like wings,
as the whale reaches the height of the breach.
A humpback whale breathes air at the surface of the
Water through two blowholes which are located near the top
of the head. It blows a double stream of water that can rise
up to 4 meters above the water.
The humpback has a small dorsal fin located towards
the tail flukes about two-thirds of the way down its back.
other distinguishing features include large pectoral fins,
which may be up to a third of the body length, and unique
black and white spots on the underside of the tail flukes.
These markings are like fingerprints: no two are the same.
Humpback whales live in large groups. They
communicate with each other through complex “songs”.