Blue Whale -- Cetacean Info at Whale Songs

SCIENTIFIC NAME: Balaenoptera musculus

COMMON NAME: Blue Whale; also known as sulphurbottom, for the yellow-brown appearance of diatoms flourishing on the skin after the whales have been in polar waters for long periods of time.

DISCOVERED: Linnaeus, 1758


GEOGRAPHICAL DISTRIBUTION:

* Widely distributed in every ocean of the world
* Migrate long distances along well-known routes between rather restricted high-latitude summering grounds and low-latitude wintering grounds

EXTERNAL ANATOMY:
* Largest living animals
* Avg. adult length = 25m (males) 26.2 m (females)
* Avg. adult body weight = 100-120 tons
* Blue-gray body color
* Mottled appearance
* Broad, flattened, u-shaped head
* Dorsal fin a small nubbin located in the last fourth of the back
* Slender, pointed flipper are about 14% of body size in length
* Large blowhole splash guard
* Uniformly black baleen plates with coarse bristles
* Color often masked by appearance of microscopic algae, called diatoms, which attach the whale¹s body and produced yellowish color-only in cold waters, polar
* 29 1\2 ft. (9 m) high blow

NATURAL HISTORY

HABITAT:

* Pelagic
* Occur primarily along the edge of the continental shelves
* Also venture into deep oceanic zones and shallow inshore regions

FOOD & FEEDING:

*Shallow feeders
*Preferred food appears to be krill
*Adult blue whale may up to 8 tons of krill in a day
*Feeding takes place during the evening and early morning

LIFE CYCLE:

*Calving occurs every 2-3 yrs.
*Gestation lasts 12 months
*Weaning period is 8 months

BEHAVIOR:

*Usually found as a solitary animals or in pairs
*In feeding grounds, there may be a greater concentration of whales
*Do not dive deeply-maximum abound 200 m
*Segregation in migration- pregnant females first to migrate
*Vocalizations include low-frequency moans, pulses, buzzes, rasps, of ultrasonic clicks
*When relaxed, blows every 10-20 seconds for up to 6 min. and dives for 5-20 mins.
*When chased, can accelerate to over 19 mph (30 km\h)
*Adults rarely breach

WORLD POPULATION:

* Estimate 10,000 - 15,000 worldwide

HUMAN INFLUENCES:

* Depleted by hunting
* No real recent whaling
* Approximately 10,000 whales worldwide