Start with modelling why we have seasons.
One way of getting through the winter is to hibernate.
Students rotate between three stations (5 mins or so each):
Fur study
Look at real fur, to find the guard hairs and the fluffy underfur.
Fur for keeping warm
Feel a bottle of iced water through fur and cloths of different thicknesses.
Fat for keeping warm
Feel a bottle of iced water through a layer of fat.
Both the fat and fur stop heat from leaving your hand, so they keep it warm. They are insulators.
Bears have thick fur and a layer of fat to keep warm.
The fur and fat layers both get thicker before hibernation.
The fat is also an energy reserve for the bears. At the end of hibernation a lot of the fat has gone, as the body has used it up.
The fur also protects against wet and wind.
End with Bear food as a demonstration. Add food to a scale until it tips (at 5kg), to show just a snack for a black bear before it hibernates.
Other activity ideas:
1. Feel our heart rate and our breathing rate. When a bear hibernates its heart rate slows down (from 50bpm to 10bpm) and it breathes less (one breath every 45 seconds).
Take our temperature. When an animal hibernates its temperature drops.
2. Watch webcam of Grouse Mountain grizzly bears hibernating.
https://www.grousemountain.com/web-cams/bear-den-cam
They hibernate for about 4 months.
Bears lower heart rate to a third, but only drop body temp by a degree (like us at night).
Dormant bears do not eat, drink, urinate or defaecate, the heart rate drops from 50–60 beats/min to 8–12/beats min, and oxygen consumption is only 32% of that of actively foraging bears.
3. Lots of bear videos, and bear vocalizations at www.bear.org
Other hibernation info:
Dry fluffy snow on top of a den also holds air, which stops heat from leaving the den.
Bears need water during hibernation - they get it from their body fat, when the fat molecules are broken down for energy.
