The blue whale has mottled skin with pale gray blotches speckled over its body. The color of its body is bluish-gray. Normally, the color of its underside is blue or white. However, at times, these whales have yellowish-colored underbellies due to the accumulation of millions of cold water microscopic organisms called diatoms (algae) that usually stick to their bodies. Hence, they are nicknamed as sulfur-bottom whales because of the yellow tint of sulfur. A blue whale has a streamlined shape and elongated, tapered body with a broad, flat and U-shaped head. On top of its upper lip, there is a noticeable ridge that runs along the length of the whale up to the blowhole. At the front of the twin blowholes, there is a very big splashguard.
The flukes are wide and triangle-shaped with an extremely small dorsal fin that is situated close to its flukes. They have long, slender pectoral fins. There are about 90 to 100 pleated ventral grooves that run laterally under the chest from throat to the navel. These grooves expand during feeding when the whale engulfs water along with krill. Blue whale is a species of baleen whale. Its mouth contains more than 800 black, short fingernail-like plates of baleen that filters out food. On each side, there are 300 to 400 baleen plates.
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“Blue Whale”. The Marine Mammal Center
“Blue Whale”. Encyclopædia Britannica, inc.
“Blue Whale Description”. Whale and Dolphin Conservation Society (WDCS)
“Blue Whale”. WWF Global