Get your Owl Eyes working........we're going to examine patterns and puzzles in nature. How DO those animals hide so well?
The science of sleep shows us some fascinating things about the hours we and other mammals spend asleep. Who "hibernates" and who just "sleeps" or is there a difference? What happens to the hibernating animal's body when they go into this state? Is this different from what our bodies do in deep sleep phases? Can humans hibernate?
We found some surprising answers: yes, humans can hibernate if needed, and maybe even on purpose! Tibetan monks can lower their oxygen needs about 60% when they are meditating. Scientists have isolated a gas called hydrogen sulfide that induces a hibernation-like state in mammals with only 10% of the oxygen needs during regular sleep. Could come in handy when traveling to Mars, or after a surgery to allow the body to heal. (Growth hormone releases increase during sleep which makes sleeping the time we do a lot of healing.)
The basic cycle of a hibernating bear in Minnesota - normal activity, hyperphagia (eating a lot), preparation for hibernation (by reducing food, but drinking more), hibernation and "walking hibernation" (the wake-up phase where low amounts of food are consumed) - is modified in warmer climates like North Carolina, where the bears will wake up several times during winter. And if weather gets too cold in Minnesota, the dropping temperatures in the bear's hibernaculum (or den) signal it to wake up and begin to shiver so it stays warm. So climate seems to play a role in whether or not a particular species hibernates in the traditional sense. But there are degrees of "sleepiness" based on where the animal lives.
We recorded how our pulse speeds up with activity and slows down with resting, as does our breathing rate. We tested how cold winter winds affect our body temperatures, and built a hibernaculum (winter shelter) to protect us.
Research question for the week is: What do you line the bottom of your den with in order to keep the cold from the earth from seeping up while you sleep? Hint: it creates air pockets.
Most people immediately think of tropical rainforests when someone says "canopy" but the truth is that any and every forest has a canopy layer. So there are canopy-living species right here in our deciduous hardwood forests of North Carolina. The main difference is that in the tropical rain forests, there is much greater diversity of species that have adapted to specific living conditions at certain heights in the trees. Many of our canopy species tend to utilize the understory and forest floor as well (think squirrels!)
For example, tropical epiphytes (a kind of plant) live on tree branches and get their moisture from fog. Research has shown in that if the plants are moved onto lower tree limbs where they don't get as much water, they begin to die. So the height at which they grow seems to be tied to the moisture level they need. (There may well be other factors as well.)
Here's an interesting research question for all you scientists to pursue more: what changes occur to the heights of cloud layers as global temperatures rise?
One well-loved canopy species has been in the news a lot the last few years due to destruction of the of the tropical lowland forests in Madagascar. The lemur is a leaf-muching, tree-climbing critter that can NOT hang by its tail. In class this week we had a Madagascar Forest Council to see if we could figure out ways to help the lemurs and their forest friends peacefully coexist with humans. Here's a link to a website with additional information on the situation. Our project this week was making Golden Lemur masks (see pic above), which we wore to the Council meeting.
A great way to experience canopy life is to go on a canopy tour! There are some cool zip line tours right here in the North Carolina mountains.