What I Read -- Winter World: The Ingenuity of Animal Survival

I stumbled upon Summer World and Winter World back when I was working at a bookstore.  They caught my interest then, and shortly thereafter, I discovered that my dad had (and was planning to give away) a copy of Winter World.  I snagged it, and decided that this winter is as good a time as any to read about the north woods' winter creatures.  (Little did I know that this would turn out to be some of the coldest winter in several years in the Midwest.)

I was quite nervous when I began this book, and the introduction described many different types of hibernation.  I anticipated that he would be referring to these different types of hibernation throughout, and I would be expected to know which was which.  "Wait, does that type of hibernation include lowering body temperature?"  (Turns back to introduction to try to figure it out....)  I made a glossary for myself.

Thankfully, that turned out to be unnecessary.  Once you get through the intro, the remainder of the book is readable, and quickly so.  It's a fascinating, albeit limited, survey of some of the creatures that forego winter migration in favor of adaptations which allow them to survive the frigid temperatures.  Geographically, the author focuses on critters he has personally observed near his cabin in Maine.  (He isn't just a casual observer, though -- he is a professor emeritus of biology at the University of Vermont.)  

It's clear from the book that he is a great lover of birds, which are the focus of many of the chapters.  Earlier in my life I may have been put off by this, but I have taken a bit more of an interest in birds in the last couple of years.  It's not all birds though.  There is discussion of bears, squirrels, bees, beavers, and lots of other wild things.  

In case you're curious what kind of strange stuff happens, here's an excerpt from a chapter on frogs:
"When ice crystals begin to form on or in the skin of a wood frog, it sets off an alarm reaction.  Skin receptors relay the message of freezing to the central nervous system (CNS), and the CNS activates the adrenal medulla to release adrenaline into the bloodstream.  When the adrenaline circulates to the liver, it there activates the enzymes that convert the liver’s stores of glycogen to glucose.  As a result, the frog responds with a quick rise in blood glucose.  In the wood frog, this response is massive and before the ice reaches the cells they become packed with glucose that acts as an antifreeze.  Precisely the opposite occurs outside, between the cells, where special proteins act as ice-nucleating agents to promote ice crystal formation in areas of dilute fluid.  As a result, pockets of concentrated fluid are created, and these act to osmotically withdraw water from the cells, making them even more resistant to ice formation.  In about fifteen hours, the frog is frozen solid except for the insides of its cells.  Its heart stops.  No more blood flows.  It no longer breathes.  By most definitions, it is dead.  But it is prepared to revive again at a later date."

All in all, fascinating -- frogs and otherwise.

Plus, I get to check one of the books off my 2021 reading challenge!

P.S. If you're curious to hear a little more about the book, try this NPR story.  If you want to read more about the author's personal background and development into a forest-dwelling loner and forest lover, here is a profile from Outside magazine.