Nature Bulletin No. 44   December 8, 1945
Forest Preserve District of Cook County
Clayton F. Smith, President
Roberts Mann, Supt. of Conservation

****:ANIMAL HIBERNATION

Many animals in this northern region go into a winter sleep, called 
"hibernation". They usually retire to some place where they do not 
actually freeze, or where they at least are protected from zero 
temperatures.

Birds do not hibernate but most species migrate to warmer regions Fish 
to not hibernate but withdraw to deeper waters and their body processes 
slow down to the point where tbeir food and oxygen requirements are a 
tiny fraction of the needs during summer months Aquatic insects do not 
hibernate. Most land insects die, leaving behind them their descendants 
in the egg, larva or pupa stages. Some insects, though, as for instance 
certain species of mosquito, hibernate in basements, cisterns and such 
protected places.

The honeybee has a thermostatic solution for existing through sub-zero 
temperatures. In moderately cold weather they remain quietly in the 
hives. But as the temperature drops each swarm suddenly begins to 
buzz and move around in the hive, which raises its temperature above 
the danger point -- just as a man thrashes his arms to keep warm.

Snakes, lizards, toads, frogs, salamanders and most kinds of turtles 
hibernate . A few turtles, such as the common painted turtle, are more 
or less active under the ice all winter. Earthworms burrow deep m the 
earth below the frost line.

The mammals, being warm-blooded, vary according to their ability to 
find winter food. The squirrels are out searching for food after each 
storm, The raccoons, opossums and skunks "hole up" and stay lethargic 
during prolonged cold snaps.

Certain species, notably bears, woodchucks (or groundhogs), gophers, 
chipmunks and bats, really hibernate. They instinctively prepare for 
their long sleep by eating heavily and accumulating fat, Then they retire 
to their dens. Some are light sleepers and, on mild winter days, may 
come out and indolently move about But some become completely 
dormant. Their body temperature falls as much as 50 degrees. The heart 
beats feebly, and breathing takes place only at long intervals and 
slowly.  The excretions are slight.  Their metabolism -- the body 
process -- is so lowered that the consumption of stored fat is very slow.  
They sleep.

We suggest that you do not hibernate, but get out and walk a lot, this 
winter!