Types

• There are true seals and eared seals. True seals do not have ear flaps and have short, broad flippers that make them awkward on land, where they drag themselves by their front flippers. True seals have well-developed back flippers that make them efficient swimmers. Eared seals have flaps over the ear openings, which is why they are referred to as eared seals. They also have longer flippers that rotate, allowing them better mobility on land than their true-seal relatives.
  
  

Features

• Seals have sleek bodies with wide, flat flippers. They have large eyes that can see well in and out of water. Their nostrils close automatically when they swim and dive. Seals have thick, waterproof fur and a thick layer of blubber that insulates and protects them from the cold. Their whiskers are sensitive allowing them to detect changes in the water that make them effective hunters. The seal's diet consists of krill, fish, shrimp and other marine life.
  
  

Significance

• The strong, muscular body of a seal is perfectly suited for living in the water and swimming. The back flippers help seals to be excellent swimmers. Seals can swim 11 to 12 mph. Depending on the species, seals can dive to depths between 300 and 1,000 feet. Seals surface to breathe; adult seals can hold their breath for at 30 minutes or more. True seals swim in a side-to-side motion like fish. Seals are usually solitary swimmers.
  
  

Size

• There are 33 species of eared seals and 18 species of true seals. The species differ in size and weight but males are generally larger than females. The Galapagos fur seal is the smallest seal weighing about 65 pounds and is about 4 feet long. The Southern Elephant seal is the largest, weighing up to 2,000 pounds and growing to 13 feet long. Although lifespan varies with the species, the average lifespan of a seal is 25 to 40 years.
  
  

Considerations

• Seals mate and give birth on land. Some species of seals are territorial and will fight over females. Male seals are called bulls; females are known as cows. A female seal gives birth to one pup after a gestation period of 9 months. Pups are born with the ability to see immediately and some species can swim within a few minutes of birth.
  
  

Geography

• Seals are adaptable creatures. Most of them live in the Arctic and Antarctic. They can survive harsh weather and cold water but they enjoy basking in the sun. Some species of seals are found in temperate waters. Seals inhabit a variety of habitats where there are islands, sandbars, ice flows and rocky shores. Although seals do not normally migrate, they will sometimes travel in search of food.