Fin Whale Vs Blue Whale, The fin whale is one of the rorquals, a family that includes the humpback whale, blue whale, Bryde’s whale, sei whale, and minke whale. Rorquals all have a dorsal fin and throat grooves that expand when the animal is feeding. The fin or finback whale is second only to the blue whale in size and weight.
Among the fastest of the great whales, it is capable of bursts of speed of up to 23 mph (37 km/hr) leading to its description as the “greyhound of the sea.” Its most unusual characteristic is the asymmetrical colouring of the lower jaw, which is white or creamy yellow on the right side and mottled black on the left side. Fin whales are found in all oceans of the world, though they seem to prefer temperate and polar waters to tropical seas.
Physical Description of Fin Whale
The fin whale is long, sleek, and streamlined, with a V-shaped head which is flat on top. A single ridge extends from the blowhole to the tip of the rostrum (upper jaw). There is a series of 50-100 pleats or grooves on the underside of its body extending from under the lower jaw to the navel.
The fin whale is light grey to brownish-black on its back and sides. Two lighter “coloured” chevrons begin midline behind the blowholes and slant down the sides towards the fluke (tail) before turning and ending right behind the eye. The underside of its body, flippers, and fluke are white. The lower jaw is grey or black on the left side and creamy white on the right side. This asymmetrical colouration extends to the baleen plates as well and is reversed on the tongue.
Fins and Fluke
The fin whale has a prominent, slightly falcate (curved) dorsal fin located far back on its body. Its flippers are small and tapered, and its fluke is wide, pointed at the tips, and notched in the centre.
Length and Weight
Adult males measure up to 78 feet (24 m) in the northern hemisphere, and 88 feet (26.8 m) in the southern hemisphere. Females are slightly larger than males. Weight for both sexes is between 50-70 tons (45,360-63,500 kg).
Fin whales feed mainly on small shrimp-like creatures called krill or euphausiids and schooling fish. They have been observed circling schools of fish at high speed, rolling the fish into compact balls then turning on their right side to engulf the fish. Their colour pattern, including their asymmetrical jaw colour, may somehow aid in the capture of such prey. They can consume up to 2 tons (1,814 kg) of food a day. As a baleen whale, it has a series of 262-473 fringed overlapping plates hanging from each side of the upper jaw, where teeth might otherwise be located.
These plates consist of a fingernail-like material called keratin that frays out into fine hairs on the ends inside the mouth near the tongue. The baleen on the left side of the mouth has alternating bands of creamy-yellow and blue-grey colour. On the right side, the forward 1/3 section of the plates is all creamy-yellow. The plates can measure up to 30 inches (76 cm) in length and 12 inches (30 cm) in width. During feeding, large volumes of water and food can be taken into the mouth because the pleated grooves in the throat expand. As the mouth closes water is expelled through the baleen plates, which trap the food on the inside near the tongue to be swallowed.
Mating and Breeding
Adult males reach sexual maturity at about 6-10 years of age. As in some other whales, sexual maturity is reached before physical maturity. Gestation is 12 months, and calves are believed to be born at 3-4 year intervals. Length at birth is 14-20 feet ( 5.5 -6.5 m) and weight is 2 tons (1,814 kg). Calves nurse for 6-8 months and are weaned when they are 30-40 feet (10-12 m) in length.
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source from save the whales