Blue Whale - Balaenoptera musculus
Desricption:
Blue Whale, largest whale and the largest creature known to have ever inhabited the earth. Blue whales may reach lengths of 29 m (95 ft); mature females tend to be slightly longer than mature males.Blue whales have a light grey and white mottled pattern, and they tend to appear light blue when just below the surface on a sunny day. The mottled pattern is distinctive for each animal, and has lately been used by researchers to identify individuals for information on movements.
Blue whales have a small dorsal fin set far back on the body. They feed by rapidly lunging into dense clouds of invertebrates such as small crustaceans, or schools of fish. As water and food rushes into the mouth, over 60 throat pleats expand, like an accordion, and the throat, or gular pouch, forms a huge bag extending from the front of the snout to the navel.
The whale then closes its mouth almost completely, leaving open a gap of about 50 cm (20 in), and forces water out through 270 to 390 pairs of black, broad, bristly baleen plates which hang from the roof of the mouth and serve as a sieve, or net. The food is caught on the inside of the plate fringes and is swallowed once the water has been expelled.
Blue whales often lunge through their prey in pairs, the two whales side-by-side, each whale apparently using the other one as a wall preventing the crowded prey from escaping.
Blue whales have one offspring at a time and nurse it for almost one year.
Blue whales produce loud low-frequency moaning sounds that can be heard in deep ocean waters for more than 160 km (100 mi). It is likely that they communicate with these moans, and a group of blue whales may therefore occupy a vast expanse of ocean.
Environment:
They are found in all oceans, and most populations appear to migrate extensively, from the tropics or near-tropics in winter to the pack ice edges of both hemispheres in summer.Food:
These gigantic whales feed entirely on small planktonic crustaceans.Problem:
They were heavily hunted from the 1930s to 1960s, and almost became extinct.Solution:
Blue whales are now protected, and may be making a slow comeback in several areas of their range.
Information provided by: http://members.optusnet.com.au.