Fat or Feathers?

How do polar animals survive and thrive in their harsh environments? There are two main methods that these animals use to stay warm in their icy habitats: blubber and fur (or down). Walruses, whales, and many seals have a thick layer of blubber insulation. This blubber is highly vascularized to insulate them from the intense cold of their water habitat, while also providing buoyancy. On the other hand, animals such as penguins and polar bears rely primarily on their body coverings for insulation. (Although penguins and polar bears both have fat, this is not their major insulator.) Penguins are extra special because their outer, overlapping feathers are waterproof, while each of those feathers has a downy tuft at the base for extra insulation.

When I returned from my Grosvenor Teacher Fellow expedition, I knew I wanted to teach my students about these important animal adaptations. After all, many of their questions and ideas about Antarctica were about the wildlife there. Although the "blubber mitt" isaverycommon activity (no, I'm not that creative!), I was looking for something that would also teach students about how other polar animals, especially their favourite - penguins! - regulate their temperature. Enter the "feather mitt". I created this feather mitt with fluffy craft feathers using the same method as a blubber mitt (just in case you're curious to try it yourself). 

We began by examining some of my photographs from my Antarctic expedition. We have been practicing different types of non-fiction writing lately, so we began by labelling important parts of the animals like a diagram. The students were also able to use their prior knowledge to know that many Antarctic animals have a thick layer of blubber. 

Next, we practiced how to read a thermometer and predicted and measured the temperature of the ice water in our container. After the children had a chance to feel just how cold the water was, and also feel what each of the mitts felt like, we made predictions about the temperatures in each of the insulator mitts. Would one be warmer than the other? What if we put the mitts into the ice water -- would that change the temperature inside them? Indeed, when we tested it out, we saw that the temperature inside the blubber mitt was 30˚C, while inside the feather mitt it was only 10˚C. So, if feathers were that much cooler, why might it still be advantageous to have them instead of that warm, thick blubber?

"Penguins have feathers. Whales have blubber."

"Penguins have feathers. Whales have blubber."

"Seals use blubber. Penguins use down."

"Seals use blubber. Penguins use down."

Two students hold the mittens in the ice water for five minutes while the thermometer records the temperature inside the insulator. 

Two students hold the mittens in the ice water for five minutes while the thermometer records the temperature inside the insulator. 

To answer this last question, we turned to the beautiful underwater photography of emperor penguins by Paul Nicklen. Do you see the bubbles coming out from behind a swimming penguin? The air trapped between a penguin's feathers can be released like a jet stream when it is underwater, allowing for extra speed and maneuverability. And let's not forget that penguins' heavy bones allow them to dive very deeply, and that blubber would just make them float more. If you were a penguin, which insulator would you prefer?