Shubenacadie Sam may, or may not, see his shadow on Sunday. In either case I am willing to bet we will have another six weeks of winter.
After suffering through two months of cold weather and bad driving I would welcome an early spring as much as anyone. However, while our groundhogs may not be overly accurate as meteorologists, they do exhibit some interesting behaviours which enable them to survive our winters. Groundhogs, along with bats, are the only true hibernators we have in Nova Scotia. While black bears undergo a type of hibernation it differs from the real thing.
True hibernators reduce their metabolic rate, body temperature and heart rate to enable them to survive very long periods of cold weather, surviving only on the food reserves they stored as fat in the fall. Bears, on the other hand, maintain a fairly high body temperature and may wake up during the winter during periods of mild weather.
Hibernation is one type of behavior animals have evolved to deal with periods of low food availability. Many animals migrate to areas where food is more abundant. Birds are a perfect example.
Others adapt to live in an environment of snow and ice. Snowshoe hares change colour and ruffed grouse grow pectinations or little fleshy growths on their feet in late fall which serve as snowshoes to allow them to walk on the snow. Other animals, such as squirrels, remain active during the winter, but store caches of food in the fall to help them make it through until spring.
Hibernators are the masters of dealing with a harsh environment and groundhogs go through some pretty complicated physiological changes during this process.
I think everyone is familiar with our groundhog, also known as woodchucks. They are found throughout mainland Nova Scotia and can be found along the edges of fields where they feed on grass and shrubs. Late in the fall groundhogs go on a major feeding spree which allows them to build up a thick layer of fat.
Late in the fall they will seal themselves in their burrows to wait out winter. Over a period of time their body temperature will drop from a high of 37 degrees to a low of 3 degrees during the coldest days of winter. During hibernation their heart rate will also drop from a high of 80 beats a minute when actively feeding in the summer to five beats per minute. This low level of activity allows the groundhogs to exist on their fat reserves until they emerge in the spring. Even with a healthy fat buildup going into the winter groundhogs may lose up to a third of their body weight.
When they emerge in the spring groundhogs are hungry, and busy. They will actively feed on plants and twigs as they wait for the grass to green up. They also have to start a family. Mating takes place in April and the young are born in May, to begin the cycle once again. Considering how busy he’ll be when he wakes up, Shubenacadie Sam may decide to sleep in for a few more weeks.
Don MacLean is an outdoor writer and biologist who lives in Pictou County.
©2014 Don MacLean