Description
The blue whale is the world's largest living animal. In the northern hemisphere, these leviathans reach 75 to 80 feet in length and weigh up to 200,000 pounds. The largest blue whale taken was a 110-foot female from the southern hemisphere. They are mottled bluish-gray on their backs and sides. Growth of tiny plants called diatoms on their bellies gives them a yellowish color that has caused them to be named “sulphur bottom” whales. Their heads are wide and flat, and their dorsal fin is very small (one foot high) and may not be visible except when they begin to dive.
Habitats and Habits
Humpback whales migrate long distances between equatorial wintering grounds and high latitude feeding areas. In the eastern North Pacific, they winter off southern and Baja California. During the summer they may be found across the Gulf of Alaska, but they seldom enter the eastern Bering Sea. Historical areas of concentration include the eastern Gulf of Alaska, the eastern Aleutians, and the far western Aleutians. Humpback whales spend most of their time along the edges of continental shelves and are seldom seen in coastal Alaska waters. Humpback whales feed on krill and may consume several tons each day, although during much of the year they apparently do not feed at all.
Causes of Decline
An estimated 4,900 to 6,000 Humpback whales inhabited the northern Pacific Ocean prior to whaling. Between 1910 and 1966, approximately 8,200 were killed in the North Pacific, severely reducing the population. The North Pacific population is now estimated at 1,200 to 1,700 animals; the worldwide population is estimated at 8,000 to 12,000.
![[range map]](whale2.jpg) |
