Blue whale

Blue Whale (Balaenoptera musculus) is a marine mammal belonging to the baleen whale suborder Mysticeti. Reaching a maximum confirmed length of 29.9 meters (98 feet) and weight of 199 tonnes (196 long tons; 219 short tons), it is the largest animal known to have ever existed.

Anatomy and appearance

The Blue Whale has a long, slender body that can be various shades of bluish-grey dorsally and somewhat lighter underneath. The head is flat, U-shaped and has a prominent ridge running from the blowhole to the top of the upper lip. The front part of the mouth is thick with baleen plates; around 300 plates, each around one meter long, hang from the upper jaw, running 0.5 m back into the mouth. Between 70 and 118 grooves (called ventral pleats) run along the throat parallel to the body length.

Distribution and habitat

Blue whales were abundant in nearly all the oceans on Earth until the beginning of the twentieth century. They are found in the Atlantic Ocean, Pacific Ocean, Indian Ocean, and Arctic Ocean. They prefer deeper ocean waters but will come closer to the shore where the ocean floor drops off suddenly.

Behavior and diet

Blue whales feed almost exclusively on krill, though they also take small numbers of copepods. The species of this krill varies according to geographic location. Around four tons of krill are consumed each day by an adult blue whale during the peak consumption period.

Conservation status

The International Union for Conservation of Nature (IUCN) lists the blue whale as "endangered". The largest threat to blue whales is from ship strikes, as they frequently feed at depths of less than 20m, putting them at risk of collision in busy shipping lanes.

See also

• Baleen Whale
• Marine Mammal
• Krill
• International Union for Conservation of Nature