Antarctic Seals
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Although there are 35 species of seals, only six types live in Antarctica: Antarctic Fur Seals, Crabeater Seals, Leopard Seals, Ross Seals, and Weddell Seals. However, these six species make up the majority of the world's seal population. With no natural land predators, such as polar bears or man, Antarctic seals behave much differently than northern seals--showing little fear of man.
Seals are categorized into three families: true seals, eared seals (common to most zoos), and walruses (found in the arctic). All of the seals in Antarctica are true seals (no ears). Even without ears, seal hearing out of the water is as good as human's. In the water, their hearing is even better. Its theorized that seals use a type of sonar to locate food, much like what dolphins and whales use.
In addition to using sonar for navigation and locating groups of food, its believed seals use their whiskers as a form of radar. The whiskers detect movement in the water and allow the seal to zoom in a particular object. Through the use of their sonar and radar, seals can actually find food in complete darkness better than in the light.
As for their eyes, seals don't really see color but they are particularly sensitive to common sea water colors (greens, green-blues). Seals eyes have a silvery lining behind the retina, just like cats and other nocturnal/low-light hunters. This lining reflects the light back through the eye and increases the total amount of light absorbed by the eye--another necessary feature when hunting in the dimly lit depths of the oceans.
When in the water, a seal's nose closes automatically and doesn't reopen until it surface. Typically, a seal can remain underwater for 15 minutes (young) to 30 minutes (adults). This also is true of when they're sleep. Seals sleep just under the surface of the ocean and can resurface for air without waking.
Seals are categorized into three families: true seals, eared seals (common to most zoos), and walruses (found in the arctic). All of the seals in Antarctica are true seals (no ears). Even without ears, seal hearing out of the water is as good as human's. In the water, their hearing is even better. Its theorized that seals use a type of sonar to locate food, much like what dolphins and whales use.
In addition to using sonar for navigation and locating groups of food, its believed seals use their whiskers as a form of radar. The whiskers detect movement in the water and allow the seal to zoom in a particular object. Through the use of their sonar and radar, seals can actually find food in complete darkness better than in the light.
As for their eyes, seals don't really see color but they are particularly sensitive to common sea water colors (greens, green-blues). Seals eyes have a silvery lining behind the retina, just like cats and other nocturnal/low-light hunters. This lining reflects the light back through the eye and increases the total amount of light absorbed by the eye--another necessary feature when hunting in the dimly lit depths of the oceans.
When in the water, a seal's nose closes automatically and doesn't reopen until it surface. Typically, a seal can remain underwater for 15 minutes (young) to 30 minutes (adults). This also is true of when they're sleep. Seals sleep just under the surface of the ocean and can resurface for air without waking.