More than just the stars of Groundhog Day

Groundhog Day is all about an overgrown ground squirrel surviving winter. As a hibernating mammal, it gets its own special day to celebrate the triumph of spring over winter just as the contemporaneous Candlemas Day celebrates the triumph of light over darkness.

Half way there

February 2 is about halfway between the winter solstice and the spring equinox. The day is noticeably longer than it was on the solstice. Likewise, Candlemas Day, a European tradition, is the day when a year’s supply of candles is blessed. Hence light over darkness.

Light switch

It may not seem like a big deal today when the flick of a switch gives us all the light we need, but before electricity, the halfway point through winter was worth a celebration. Longer days and a new growing season became realizable promises.

In Europe, the custom was to predict the arrival of spring by watching for a hedgehog’s shadow on Feb. 2. Since North America has no hedgehogs, early Americans adopted the groundhog as a substitute harbinger, apparently unaware that most are still hibernating in early February. What I’ve never understood is why bright sunshine means six more weeks of winter, and clouds mean an early spring.

Forecasting spring

Of course, the groundhog’s ability to forecast the arrival of spring is hogwash. But groundhogs themselves are worth celebrating, if only for their contributions to soil health. Their droppings are natural fertilizers, and their burrowing activities loosen and aerate soils.

Groundhog survival

Upon emerging from their dens, groundhogs have survived a long winter’s sleep. They are gaunt and hungry. For three months their body temperature has plummeted to 40 degrees Fahrenheit, and their heart rate has dropped to four beats per minute.

Now it’s back to life; the race is on to eat, grow, and accumulate the body fat needed to survive next winter’s hibernation. If it’s green, groundhogs eat it – grass, alfalfa, clover, beans, peas, corn, and apples. For eight to nine months, they are eating machines. They forage furiously, taking just one break almost immediately to search for a mate. Breeding. Breeding right after hibernation gives the next generation of groundhogs the time needed to grow to adult size.

After a 32-day pregnancy, females give birth to four or five naked, helpless pups. This occurs in March or early April. About four weeks later the pups leave the den and begin feeding near the burrow’s entrance. Weaning occurs about two weeks later, and at eight weeks of age the pups are independent. It’s now up to them to get fat enough to survive the long winter sleep.

Juveniles take longer than adults to prepare for hibernation because they “start from scratch.” Most adult groundhogs head to their dens by mid-November. It takes young groundhogs well into November and sometimes December to accumulate the fat needed to survive hibernation. So if you see a groundhog after Thanksgiving, it’s probably a juvenile.

Reproduction calendar

The groundhog’s rush to reproduce is mandated by the calendar. That’s why I always feel badly when I see a road-killed groundhog. If it’s March, I know they’ve just made it through a long hard winter. Surprisingly, not all groundhogs survive hibernation. If they sleep just a few days too long, they starve. And if they didn’t properly seal the entrances to their burrow, they may succumb to hungry weasels. A road-killed groundhog in October is equally disturbing. It almost won the race to winter, but never reached the finish line. Its genes will not make it to the next year’s generation.

Threats

Death by vehicle is just one of many threats groundhogs face while above ground. Young pups are easy prey for red-tailed hawks. Mink, foxes, dogs, coyotes, and target shooters also kill their fair share of groundhogs.

Fortunately, groundhogs are common, and they reproduce rapidly, so they’re difficult to eliminate. But in early spring and late fall, I always breathe just a little sigh of relief when I see an adult groundhog standing upright in a hay field.