Blue whale

Blue whale - Balaenoptera musculus
Order: Cetacea 
Suborder: Mysticeti
Family: Balaenopteridae
Species: Balaenoptera musculus

Geographic Range
Blue whales are found in all oceans of the world, from the tropics to the drift ice of polar waters.
Physical Description
Blue whales are slate to grayish blue and mottled with lighter spots, particularly on the back and shoulders. The undersidesoften become covered with microorganisms, giving the belly a yellowish tinge. Because of this blue whales are sometimes called "sulphurbottoms". The dorsal fin is short, only about 35 cm. The upper jaw is the widest in the genus, and the rostrum is the bluntest. There are 50-90 throat grooves that extend from the chin to just beyond the navel.
Blue whales are the largest animals ever to exist onearth. Average head-body length in adult males is 25 m; in females it is 27 m. The longest confirmed specimen was 33.5 m in length and the heaviest was 190,000 kg.
Mass
190000 kg (high); avg. 190000 kg
(418000 lbs; avg. 418000 lbs)
Length
33.50 m (high); avg. 26 m
(109.88 ft; avg. 85.28 ft)

Reproduction
Very little is known about mating in the large whale species.
The gestationperiod is eleven or twelve months long, unusually short for an animal its size. Young are born in warm, low latitude waters in the winter months after the adults return from their high latitude feeding grounds. At birth the young are 7-8 m long. While nursing, blue whales can gain up to 90 kg in body weight a day. Young are weaned after seven or eight months, usually after attaining a length of 16 m.Sexual maturity occurs at about 5 years old in females, or at about 21 to 23 m in length and young are produced every 2 or 3 years after that. Twins are rare but do occur occasionally. Males mature at 20 to 21 m, just under 5 years old. Longevity has been estimated to be as high as 110 years.
Blue whale young are cared for extensively by their mother. Male blue whales do not contribute parentalcare.
Breeding interval
Females give birth to young every 2 to 3 years. 
Breeding season
Breeding occurs during the winter months. 
Number of offspring
1 (average)
Gestation period
11 to 12 months; avg. 11.50 months
Birth Mass
2000000 g (average)
(70400 oz)
Time to weaning
7 to 8 months; avg. 7.50 months
Time to independence
2 to 3 years
Age at sexual or reproductive maturity(female)
5 years (average)
Age at sexual or reproductive maturity (male)
5 years (average)
Life

Longevity in blue whales, and other large cetaceans, is estimated by counting the number of ovarian scars in sexually mature females, changes in the coloration of eye lenses, and counting the number of ridges on baleen plates. Age estimates of blue whales suggest a lifespan of 80 to 90 years.
Averagelifespan (wild) 85 years
Average lifespan (captivity)
110 years
Behavior
Most populations of blue whales are migratory, though some animals do not migrate. Migrators typically spend the winter in low latitude waters, move towards the poles during the spring, feedin high latitude waters during the summer and head back toward the equator during the fall. There are northern and southern ocean populations that remain distinct. Normal swimming speed is around 22 km/hr, but blue whales can make 48 km/hr if alarmed. Feeding is usually at depths less than 100 m; harpooned animals have dived as deep as 500 m. Normal dives last from 10-20 minutes and are separatedby 8-15 blows. The spout of blue whales can reach almost 10 m. Aggregations of up to 60 animals have been reported, but solitary animals or pods of two or three are more common.
How do whales stay warm in icy-cold water? |
| This is an excellent question, especially when you consider that certain species of whales live where ambient water temperatures hover around the freezing point....