Polar Bears: Much More than a Polar Pin-Up

IJsberen op Spitsbergen, augustus 2008. Photo courtesy of martha de Jong-Lantink, Flickr.

Did you know that polar bears live only in the Arctic? Many people wonder why polar bears don’t eat penguins, another animal popularly associated with the poles. In fact, these two animals live at the opposite ends of the earth! The giant marine mammals are believed to have evolved from brown bear ancestors approximately 200,000 years ago. They are found in five nations that extend above the Arctic Circle: the United States (Alaska), Canada, Russia, Denmark (Greenland), and Norway.

Did you know that polar bears really aren’t white? Each hair is a transparent, hollow shaft. The hollow core scatters and reflects visible light in the same manner as ice and snow do, causing the hair to appear white in color. Beneath the dense fur is black skin! A common myth is that this transparent hair acts as a fiber-optic guide to conduct light to the black skin where the energy can be absorbed. This theory was tested and disproved by physicist Daniel W. Koon in 1988. In his study, Koon found that the keratin protein in the hair actually absorbs much of the light before it ever reaches the skin.

A bear’s real insulation comes from its dense fur and a thick (up to 4.5 inches) layer of blubber. This insulation is so effective that overheating is a much bigger problem than heat loss. In fact, polar bears give off so little heat that they do not show up in pictures taken with infrared film. (Infrared film detects and records the amount of heat.) The only visible spot in such a picture would be the puff of air caused by the bear’s breath!

Did you know that polar bears are a vulnerable species in today’s changing world? While human impact (industrial processes, poaching, and pollution) are affecting bear populations, a loss of sea-ice habitat due to climate change is the greatest threat. Scientists predict that if current warming trends continue, two-thirds of the polar bear population could disappear by 2050. Others predict that the polar bear species may become extinct within 100 years.

Why Teach about Polar Bears?

Like penguins, polar bears are well-known polar animals. The cuddly looking bears have starred in many cartoons, commercials, and movies. But student understanding often stops with these simplistic images, or includes the misconceptions described by Polar Bears International. In fact, polar bears are fascinating creatures, well adapted to life in a harsh climate.

According to the Life Science content standards of the National Science Education Standards, K-4 students should develop an understanding of the characteristics of organisms, life cycles, and how organisms depend on their environments. Students in grades 5-8 should develop an understanding of structure and function in living systems, reproduction and heredity, regulation and behavior, populations and ecosystems, and diversity and adaptation of organisms. Including lessons or a unit on polar bears in your teaching is a great way to address topics such as camouflage and adaptation, which are included in the Life Science Standards for both elementary and middle school. You can also use the topics to illustrate how human activities and climate change can impact polar bear populations.

Teaching the Science

You may want to learn more about polar bears before introducing the topic with your students. Polar Bears International is a conservation and education group dedicated to protecting polar bears throughout the Arctic. Its web site provides a wealth of factual information, interactive features such as polar bear cams and bear trackers, current research information, and ways to get involved. Some of these features may also be appropriate for use with your students.

For K-2 students, science and literacy are heavily integrated in the following lessons. You may notice that many of these lessons include the idea that polar bears are white. While we do not want to promote misconceptions, the transparent hair of polar bears does, in fact, appear white. In this case, teaching the correct science may be too advanced for these youngest students. If you feel it is appropriate, you can introduce the idea, using snow or ice as a more concrete example of an object that appears white, but really isn’t.

In Why Are Polar Bears White? K-2 students learn about the concept of camouflage through a hands-on activity. They then apply this concept by creating a picture of a polar bear to demonstrate why its color is a helpful adaptation.

The lesson Polar Bears: Keeping Warm at the Arctic is designed for students in K-1 but could be modified for older grades as well. Students visit a local zoo to observe a polar bear, recording observations in a lab notebook. (If a field trip is not an option, video highlights such as the ones from National Geographic’s Polar Bear Cam could substitute.) Students then create a “blubber glove” with plastic bags and a shortening product, such as Crisco. By placing a gloved hand and a non-gloved hand in ice water, they can observe the insulating properties of blubber firsthand. Students communicate their findings through art, discussion, and writing. (This lesson is subject to a Creative Commons license.)

For students in grades 4-5, ThinkQuest has a one-page introduction to polar bears as part of a larger site about Arctic animals. This, along with Polar Bears International, could be a good introduction to the species before doing research or a hands-on activity like Polar Bears and their Adaptations.

A hands-on lesson designed for students in grades 4-5 is Polar Bears and Their Adaptations. After an introductory discussion of the concept of adaptation, students create a “blubber glove” with plastic bags and a shortening product, such as Crisco, and test in ice water. Students write about the experiment and their results, which are assessed through a rubric. (This lesson is subject to a Creative Commons license.)

Students in grade 4 and up can also investigate the effects of climate change on polar bear populations in Bearly Any Ice. This lesson provides background information at a variety of levels and involves a modified version of tag to simulate the predator-prey relationship between polar bears and ringed seals. Playing this game will help students understand the drastic impact of global warming by linking the amount of sea-ice and the sea ice season to the survival of the polar bear. Before participating in this activity, students should have a good understanding of climate change and the habitat and hunting behavior of polar bears. Lesson extensions could utilize the many current news articles which discuss the changes in sea-ice and the impact on polar bears’ survival.

Suggested Readings

There are many wonderful stories about polar bears. You may have books in your own collection, or your media specialist may be able to suggest favorites. We’ve chosen to highlight three award-winning books here.

Ice Bear: In the Steps of the Polar Bear. Nicola Davies. Illustrated by Gary Blythe. Candlewick Press. 2005. 32 pp. NSTA Outstanding Trade Book (2006). Recommended ages: Primary, Elementary.

Polar Bear Night. Lauren Thompson. Illustrated by Stephen Savage. Scholastic Press. 2004. Picture book. New York Times Best Illustrated (2004). ALA Notable Books for Children (2005). Charlotte Zolotow Honor (2005). Recommended Ages: Emerging Readers, Primary.

Snow Bear. Jean Craighead George. Illustrated by Wendell Minor. Hyperion. 1999. Picture book. Notable Books of the English Language Arts (2000). Recommended Ages: Primary.

Literacy Connection

ReadWriteThink has an online Animal Inquiry tool. This is an interactive graphic organizer in which students can record information about basic facts, animal babies, interaction with others, and habitats. The site includes suggestions for classroom use, as well as links to other integrated reading, research, and report-writing lessons that use the tool. While these lessons are all designed for K-2 students, they can be easily modified for use in upper elementary as well.

This article was written by Jessica Fries-Gaither. For more information, see the Beyond Penguins and Polar Bears Contributors page. Email Jessica at beyondpenguins@msteacher.org.

Copyright August 2011 – The Ohio State University. This material is based upon work supported by the National Science Foundation under Grant No. 0733024. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. This work is licensed under an Attribution-ShareAlike 3.0 Unported Creative Commons license.