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| BELUGA WHALES |
| Physical Characteristics |
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| 1. |
Adults average 3 m (9.8ft.) in length.
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| 2. |
Males average 3.4 to 4.6 m (11.2-15.1 ft.) and weigh about 1,500 kg (3,307 lb.). |
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Females average 3 to 4 m (9.8 to 13.1 ft.) and weigh about 1,360 kg (2,998 lb.). |
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| 4. |
Beluga whales reach full size at about 10 years. |
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| 1. |
A beluga whale's body is fusiform, but robust and stocky. It may have thick folds of blubber, especially along its ventral surface. |
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Beluga whales are robust and stocky with thick folds of blubber.
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Calves are born dark gray to bluish or brownish gray and become darker after the first month. Thereafter they gradually become paler. This is caused by a reduction of melanin in the skin. |
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| 2. |
Adult belugas are yellowish-white to creamy white. |
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Belugas attain their white coloration upon reaching sexual maturity - their skin begins to change color at approximately age six and is nearly all white by age 13. |
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The coloration of a beluga calf at birth ranges from dark gray to bluish or brownish gray. They lighten to the white coloration as they mature.
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| 1. |
A beluga whale's forelimbs are pectoral flippers. Pectoral flippers have the major skeletal elements of the forelimbs of land mammals, but they're shortened and modified. |
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The skeletal elements are rigidly supported by connective tissue. Thick cartilage pads lie lengthwise between the bones of each digit. Connective tissue lies between the digits. |
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The pectoral flippers are small in proportion to the body. They're rounded, paddle-like, and slightly upcurled at the tips. |
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Beluga whales use their pectoral flippers mainly to steer and, with the help of the flukes, to stop. |
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A beluga whale's pectoral flipper contains five digits
much like the fingers on a human hand.
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Each lobe of the tail is called a fluke. A deep median notch separates the two flukes.
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Flukes are flattened pads of tough, dense, fibrous connective tissue - completely without bone. |
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The flukes of beluga whales are distinctly curved along the trailing edges. |
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Longitudinal muscles of the back (both above and below the spine) and caudal peduncle move the flukes up and down. |
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Like the arteries of the flippers, the arteries of the flukes are surrounded by veins to help maintain body temperature. |
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All traces of hind limbs have disappeared except for two reduced, rod-shaped pelvic bones, which are buried deep in body muscle.
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These reduced hind limbs are not connected to the vertebral column. |
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Beluga whales lack a dorsal fin. Without a dorsal fin, they have less surface area for heat loss, and can more easily swim just below ice sheets to locate breathing holes. |
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The beluga has a dorsal ridge that runs from just behind the midpoint of the back to the tail flukes. The dorsal ridge may be notched, forming a series of small bumps, and may be dark gray. |
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Belugas have a dorsal ridge rather than a dorsal fin.
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Neck.
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The seven neck vertebrae of a beluga whale are not fused, as they are in most cetaceans. As a result, a beluga has greater mobility and flexibility in its neck. |
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The seven vertebrae in the beluga's neck are not fused giving the species greater mobility and flexibility in its neck.
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| 2. |
Rostrum.
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Beluga whales have small, but distinct beaks. |
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Teeth.
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Belugas have eight to ten peg-shaped teeth on each side of both upper and lower jaws. Belugas have an average of 34 teeth. |
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Teeth are adapted for grasping and tearing rather than chewing. |
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Melon.
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The melon is a rounded structure on the dorsal surface of a whale's head, just in front of the blowhole. On beluga whales it is prominent and overhangs the rostrum. The melon is composed of lipids (fats). |
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A beluga's melon is generally more flexible compared to other whale species. |
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The melon probably facilitates sound production. It changes shape when the whale is producing sounds. |
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The rounded, flexible melon on the forehead of belugas probably facilitates sound production.
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Eyes.
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A beluga whale's small, dark eyes are located behind the corners of the mouth. |
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Ears.
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Ears, located just behind the eyes, are inconspicuous openings with no external pinnae (flaps). |
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Blowhole.
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A single blowhole, located on the dorsal surface of the head, is covered by a muscular flap. The flap provides a water-tight seal. |
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A beluga whale breathes through its blowhole. |
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The blowhole is relaxed in a closed position. To open the blowhole, a beluga contracts the muscular flap. |
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| 1. |
Like most other cetaceans, beluga whales lack hair as adults.
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| 2. |
Unlike other cetaceans, which tend to generate and shed skin continuously, beluga whales appear to undergo a seasonal molt of the outer layer of skin. During the winter, the top layer of a beluga's skin may turn yellow, especially on its back and flippers. Rubbing on gravel river bottoms helps a beluga to shed this layer of skin. |
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