Brown Bear Hibernation Task

Each winter brown bears in North America spend an average of 5 months inside of dens in a low activity state known as hibernation. During this time, they experience drastic body changes. They also do not eat, drink, defecate (poop), or urinate (pee) during this time. It is a wonder that the bears can survive each winter in this state without performing these essential body functions!

Use what you’ve learned from our investigations related to M’Kenna’s case and the data above to explain this phenomenon.

During hibernation, bears do not eat for 5 to 6 months in a row. How can the bear stay alive without eating for this long? Use patterns in the data table and science ideas developed throughout this unit to support your answer.

To prepare for winter in the den, a bear will gain up to 30 pounds a week (in extra mass) by eating grass, roots, berries, fish, insects, and small animals. Using everything you’ve learned from the unit, develop a model that explains, “How a bear can gain so much weight so quickly?” Some important components or interactions to include in your model are: food molecules, matter, energy, chemical reactions. Use extra sheets of paper for your model. The components you should include in your model are: Blood, Cells, Fat stores, Lungs, Oxygen, Carbon Dioxide, Energy, Bite of food, Food molecules. Some interactions you should include in your model are: Digestion, Absorption, Eating, Excretion, Delivery to cells, Inhaling and exhaling. Please give an explanation of your model here.

In spring, when the bears emerge from their dens, they have lost between 15% and 30% of their body weight (mass)—that could be around 120 pounds for a large brown bear! Explain where all the mass went when it was “lost.”

In the last few years, scientists and citizens have noticed that bears in North Carolina are larger than ever. Black bears in North Carolina are usually about 400 pounds maximum, but recently scientists have found bears greater than 700 pounds. Make a prediction about food availability in North Carolina in the last few years. Use your model to support your prediction.