The season of winter is approaching, as evidenced by the accompanying photo of the accumulation of snow sent to me by Gregg Betts of Cassadaga. This is a time when most of the plant and animal species in our area begin to make provisions for survival through a relatively difficult period.
While many of our plant and animal groups are capable of survival, as we have evidenced over the years, several species of both groups must make physical and biological provisions to do so. Since the animal world is most familiar to the majority of us, I will start with a discussion of their methodology of survival at the time of extreme weather conditions, even though there are many scientists who maintain a discussion on the term "global warming."
I would like to begin this topic by defining hibernation. I suspect that there are few of you who are not familiar with this subject. The untold stories of bears and other animals that we have learned in school that hibernate (or do they call it winter sleep?) are not unfamiliar to us. When I was a science student in college, I remember my professors discussing the terms "hibernation" and "aestivation" as terms for survival under extreme weather conditions. In this case, it does not always apply to winter conditions, but may also refer to extreme heat situations that may aggravate specific life forms during summer months.
The Black Bear, top left, hibernates, while the Caddis Fly and American Toad, above, experience aestivation.
One of the most familiar examples of hibernation is that of the Black Bear. The life processes of an animal such as the Black Bear slow down during hibernation. However, the normal life processes of an animal in this state will cause the animal to occasionally awaken during warm spells and move about. By contrast, the well-known Woodchuck is another example of an animal that is a winter sleeper. This little mammal usually seeks shelter during adverse weather conditions and will go into a physiological state in which it can live for long intervals like this. In this state, the animal can survive by way of a decreased metabolism so greatly lowered that it can survive on little food and oxygen.
This is unlike a bird like the Swallow or some other animal species that leaves a place with difficult conditions and moves, through migration, to a more accommodating situation, which means avoiding any major physiological changes. At the same time, some other members of the mammal world, such as the fox and rabbit, remain fairly active during these adverse conditions.
The term "aestivation" is usually applied to summer dormancy. The larvae of some aquatic insects, such as the Caddis Fly (a little insect that many of my students and I searched for in flowing streams when I was teaching), have a way of surviving during periods of drought by sinking to the bottom of the water habitat it lives in. Two more very common animals that survive by the process of aestivation are several species of frogs and toads. For example, the American Toad, when in a state of aestivation, slows several of its body processes down to survive nocturnal periods.
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