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photo gallery > Marine Mammals - other (9)
Dall's porpoise and Northern river otters
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dall-underwater.jpg
Click image to view full size. Dall's Porpoises are hugely active creatures. They will often zigzag around at great speed on or just below the surface of the water creating a spray called a "rooster tail". They may appear and disappear quite suddenly. The fastest of all small cetaceans, and coming close to matching the mighty Orca for speed, Dall's Porpoises can swim at up to 55 km/h. The porpoises will approach boats and will bow- and stern-ride, but may lose interest, unless the boat is travelling quickly. -
dall-underwater-3.jpg
Click image to view full size. Here is something that you will only see with the help of photography. This Dall's porpoise was moving through the water at incredible speed yet my camera captured this moment of reflection and composition that stands as one of my favourite photoraphs of the season.
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dall-underwater-2.jpg
Click image to view full size. The unique body shape of the Dall's Porpoise makes it easily distinguishable from other cetacean species. The animal has a very thick body and a small head. The colouration is rather like that of an Orca— the main body of the porpoise is very dark grey to black with very demarcated white patches on the flank that begin some way behind the flippers, which are small and close to the head. -
dall-underwater-4.jpg
Click image to view full size. Many Dall's Porpoises are killed each year as bycatch in fishing nets. A serious cause of concern is the hunting of Dall's Porpoises by harpoon by Japanese hunters. The number of porpoise killed each year rose dramatically following the moratoria on hunting larger cetaceans introduced in the mid-1980s. 1988 saw the greatest number, 40,000, killed. A quota of 18,000 individuals per year is now in operation. However, concern remains that this is sufficient to deplete populations in the western Pacific. -
river-otter-1.jpg
Click image to view full size. The Norther river otter can tolerate a great range of temperature and elevations; its main requirements are a steady food supply and easy access to a body of water. However, the Northern river otter is sensitive to pollution, and will disappear from polluted areas.
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river-otter-2.jpg
Click image to view full size. Although commonly called a "river otter", the name can be misleading, as it inhabits marine as well as freshwater environments. Some populations permanently reside in marine shoreline habitats. They differ from sea otters, however, in the fact that they spend a far greater percent of their time on land.
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river-otter-3.jpg
Click image to view full size. Since the discovery of the Americas, hunters have captured and killed the otters for their pelts. Hunting still continues today, otter pelts being worth over $100 (USD) each. Over 30,000 otter pelts are sold each year in the United States and Canada. -
river-otter-4.jpg
Click image to view full size. The Northern River Otter mainly eats fish, but also eat insects, frogs, crustaceans (like the crab seen here) and sometimes small mammals. On occasion some larger river otters will attack and kill water birds such as ducks, geese, and even herons. -
river-otter-5.jpg
Click image to view full size.The reproduction of a river otter is a very complicated process. When a male attracts a female, they play before they actually mate. After, the female follows the male to his den, then mates in his bed, and they romp and wrestle while mating. The gestation period is about 5-7 weeks until the cubs are born. In early spring, the cubs nurse with their mother until they are about 1/2 months old. At 3 months they leave their mother's den.
