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Callorhinus ursinus Region: Temperate Northern Pacific and sub-arctic Coastal waters, open ocean, specific islands for breeding |
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Conservation Status: Vulnerable  |
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Seals at sea Ears make the difference Northern fur seals are pinnipeds (or "fin-footed"), marine mammals that include three families: fur seals and sea lions, walruses, and true seals. Northern fur seals and sea lions are members of the "eared seal" group. The distinguishing characteristic of eared seals is, you guessed it, ears. The ears are little more than tufts of skin and fur that stick out, but it’s enough to distinguish them from true seals, which have no external ears. Another difference is that eared seals can bring their hind flippers forward to help them walk, while the hind flippers of true seals extend behind them, and play no role in locomotion on land. The flippers of all species come in "hand-y" while swimming, however. The big and the small of it Male Northern fur seals are big, burly animals with massive necks. The males, or bulls, can weigh upwards of 700 pounds (272 kilograms). By contrast, females weigh about 100 pounds---about 80% smaller than the males! There’s such a big difference in size between the sexes (a trait called sexual dimorphism) that the females look like "mini versions" of the males. A migration sensation Northern fur seals are the kings of pinniped travel. Certain populations migrate more than six thousand miles (10, 000 kilometers) every year to and from breeding sites. Northern fur seals occupy a huge range of ocean, but their all- important breeding sites are a few relatively small islands scattered in the cold coastal Pacific waters. In spring, the seals begin a migration toward the breeding sites and by summer and early fall the islands are teeming with seals. A breeding group of fur seals, called a rookery, bustles with activity. Big males jostle and battle for the best positions on the beach to attract and defend their females. Males may return to the same site year after year if they are able to successfully defend it. After mating, the seals return to the ocean and by winter the islands are seal free. Treading water With all the travelling they do, it’s no wonder that Northern fur seals spend most of their time in the open ocean (animals that do this are called "pelagic"). When they aren’t fishing for food at night, or swimming on their long journey, they’re sleeping during the daylight hours. How do you sleep in deep water? Seals are naturally buoyant because of a thick layer of blubber under the skin, so floating is no problem for them. The dense fur on their body keeps them warm. When Northern fur seals sleep, they roll over on one side, fold a hind flipper up on their stomach, hold it in place with a foreflipper, and snooze away. Jug "hands" Seals also have another swimming position that serves a cool (or hot!) function. They have plenty of blood vessels in their big flippers, giving them a large area of skin over which to control their body temperature. They might swim with their flippers up and exposed to the cool air to dissipate heat—this is sometimes called "jugging." They do a similar thing to warm up, floating with their front flipper arched over the back flipper to keep those blood vessels warmed up. This position (similar to how they sleep) is also called "jugging" or sometimes "jug handling" because with their flippers folded up they look a little like a jug---with handles! Just the facts Length: Males 6.9 feet (210 centimeters) Females 3.3 to 4.7 feet (100 to 142 centimeters) Weight: Males 396 to 700 or more pounds (180 to 317 kilograms) Females 66 to 130 pounds (30 to 58 kilograms) Habitat: Temperate Northern Pacific and sub-arctic Coastal waters, open ocean, specific islands for breeding Distribution: Northern fur seals are listed as Vulnerable in the IUCN Redlist (a species is Vulnerable when it is not Critically Endangered or Endangered but still faces a high risk of extinction in the wild in the medium-term future.) Fur seals were once hunted on land and in the open ocean for food and pelts, resulting in a dramatic decline in the species. After the U.S. government prohibited pelagic hunting (taking animals in the open ocean), the population was able to recover somewhat. Northern fur seals were not protected on their breeding grounds, however, and the population declined again after intensive hunting of females between 1952 and 1962. Since the mid 1980s, hunting has been illegal on the breeding grounds, with the exception of subsistence hunts (2,000 animals or less per year) by native peoples. A small amount of bycatch has been permitted in the fishing industry, yet many Northern fur seals die in drift nets each year. Despite efforts to control hunting, the Northern fur seal population has shown little recovery. This species has been observed as "particularly sensitive" to environmental changes such as pollution and El Niño and El Niña events. Wild diet: Small schooling fish, such as anchovy, herring, and squid BZ diet: Herring, capelin, and squid Northern fur seals at Brookfield Zoo Two male Northern fur seals, named Hagar and Baranov, are brand new residents at the zoo. They live in the recently revamped Pinniped Point, along with walruses, sea lions, and harbor seals. Brookfield Zoo participates in a multi-institutional effort to manage populations of Northern fur seals, a species vulnerable to extinction. Wild Northern fur seal populations suffered a severe decline in numbers since the middle of last century due to overhunting, and the populations do not appear to be recovering well. Brookfield Zoo is one of five facilities in North America that exhibits Northern fur seals. Links |