As the temperature drops here in New England, we are thinking of animals that thrive in cold environments every day. Antarctica, the cold icy desert where temperatures rarely reach above freezing is a land mass is surrounded by the Antarctic Ocean where temperatures hover just above the freezing temperature of seawater (28.4 F). Yet this area is home to penguins, whales, seals and other animals.
What are they doing there?
There is a huge seasonal food supply. There is enough to sustain the blue whale, which eats at least 4 tons of krill each day in the summer.
More importantly, how are they surviving?
The first thing to consider is these animals are warm blooded, meaning they maintain a constant body temperature by generating heat from within by metabolic activity.
In the cold temperatures of Antarctica, they must generate enough heat and then keep it. They need to take in energy in the form of food, and that combined with their adaptations, allows them to retain it.
Adaptations that help them stay warm:
· They are large in size (you aren’t going to find any ants in Antarctica). This helps prevent loss of heat through the skin (lots of volume, low surface area).
· Smaller extremities like flukes (whale tails) and flippers prevent heat loss.
· They are well insulated. Blubber insulates them from the water, while fur and feathers insulate them from the air.
· They are carnivores. Meat is high in energy and easy to digest.
· They huddle for warmth (penguins).
· Whales and dolphins stay in the water.
· Seals enter the water when the air becomes too cold or windy.
· They migrate north when the air temperature drops enough to freeze the surrounding water.
· Some have countercurrent heat exchangers in their flippers and feet. These parts are kept at lower temperatures to conserve heat. Blood is cooled when it enters and warmed when it leaves the flippers or feet.
Activity: Blubber Gloves
In this experiment, students will test the difference between an animal with and without blubber and learn about adaptations of animals who live in the Arctic.
One pair of small, thick rubber gloves
One pair of larger, thick rubber gloves (fit over the small pair)
Crisco / shortening
Spatula or spoon
Bucket of ice water
Have one student put on the smaller rubber gloves. Have another student smear shortening over one of the gloves (up to the wrist area) and place the larger gloves over top (on both hands). Fold the ends of the gloves toward the wrists to create a cuff and loosely place duct tape on the cuff to create a seal. The student wearing the gloves can place both hands in the bucket of ice water for at least ten seconds.
If the gloves are removed carefully, they can be passed to the next student to try.
What does the glove with the shortening simulate? What does the glove without the shortening simulate?
Which hand was warmer? Why? What does this tell us about animals who can survive in cold temperatures?
Cool Antarctica (n.d.). How animals survive in cold conditions – science of the cold. Retrieved from http://www.coolantarctica.com/Antarctica%20fact%20file/science/cold_all_animals.php
Rubber Blubber Gloves. Retrieved from http://www.amnh.org/ology/features/stufftodo_marine/blubber_do.php