Ch3 L2 Adaptations

Ch3 L2 Adaptations

Cool Fact

Unlike most whales, beluga whales have a flexible neck and can swim backward. These abilities help them move in and around ice- covered areas and avoid getting trapped in tight spaces. 

A thick blubber layer accounts for up to 40 percent of a beluga whale’s total body mass. 

The Arctic is home to more than a dozen species of marine mammals. Marine mammals spend most of their lives in the ocean or depend on the ocean for food. Like all mammals, they have fur on their body at some point in their life, are warm-blooded, breathe air, and feed on their mother’s milk when young.

Classifications

Some Arctic marine mammals are in the Arctic region year-round. Others are there only part of the year. Most fall into two groups: cetaceans (sih TAY shunz) and pinnipeds (PIH nih pedz). 

Arctic cetaceans include the bowhead whale, the beluga whale, the narwhal, and several other whale species. 

Multiple Choice

What is the purpose of the Narwhal Tusk, most commonly found on males?

• It is a tooth and they use it to catch food.

• It is for attracting a mate, sometimes growing up to 10 feet long.

• None because it is not a real animal.

Pinnipeds

Pinniped means “fin-footed”—these mammals have four fins instead of hands and feet. The Arctic pinnipeds include the bearded seal, the ringed seal, the harp seal, the hooded seal, the ribbon seal, the spotted seal, and the walrus.  

The polar bear is the only Arctic marine mammal that is not a cetacean or a pinniped.

Adaptations

Marine mammals living in the cold and icy Arctic have several adaptations (a dap TAY shunz) to help them survive there. Adaptations are body parts, behaviors, or colorations that help living things survive in a particular environment. Marine mammals of the Arctic have all three kinds of adaptations. 

Multiple Choice

What is an adaptation artic marine animals have that help it stay warm because it acts like a thermal insulator?

• oobleck

• blubber

• slime

• flubber

Blubber—a layer of fat under the skin

Blubber helps an animal keep its body heat inside instead of losing it to the chilly Arctic water and air. It works the same way a coat works for you in cold weather. The coat does not make its own heat, but it helps keep your body heat from escaping. 

The blowhead whale has the thickest blubber layer of all cetaceans—up to 20 in. (50 cm) thick. 

Diving Reflex

A shared behavioral adaptation among all marine mammals is the diving reflex. This is the slowing of the heart rate and other changes that take place in a mammal’s body when cold water contacts the face.  

When a mammal dives into cold Arctic waters, one of the first changes to happen is the slowing of the heart rate, also called bradycardia (bray dee KAR dee uh). For example, a ringed seal’s heart rate can drop from 140 beats per minute to less than 10 beats per minute during a dive.  

Another change is that some of the animal’s blood moves away from its limbs and toward its heart and brain. These changes help the animal use less oxygen and stay underwater longer. The diving reflex is strongest in marine mammals, but it is present in all mammals—even humans. 

Color Adaptations

Several Arctic marine mammal species have coloration adaptations, too. Harp seals and ringed seals are born white to help them blend into the snow and ice until they are better able to defend themselves.  

Multiple Choice

TRUE OR FALSE: A polar bear's coat is so well camouflaged in Arctic environments that it can sometimes pass as a snow drift.

• True

• False

Did you know?

The coloration adaptation is actually an illusion. Polar bears do not have white fur or skin. Each hair in a polar bear’s coat is see-through, and polar bear skin is black. However, when light hits the bear, the thick fur reflects all colors, making it look white. 

The polar bear’s coat has no white pigment.

Next steps

Animal Adaptation Videos