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Groundhog Day: It's about sex, not the weather

This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American



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Bad news for all you cold-weather wimps: Punxsutawney Phil saw his pudgy shadow this morning, foretelling six more weeks of winter—if you believe the Groundhog Day legend.

Actually, Phil likely had more, ahem, urgent matters on his mind this chilly morn (unless, as USA Today's The Weather Guys blog suggests, he was just peeved at being awakened after celebrating his home state’s Super Bowl win by the Steelers last night). Groundhogs who emerge from hibernation in the dead of February are checking out their mating prospects, according to a Penn State study.

Groundhogs, aka woodchucks, stop hibernating in early March. But the male rodents emerge from their burrows periodically during their four-month hibernation to visit potential partners, according to research published in 2003 in the Journal of Mammology. And they really are just visits; they don't mate until March, according to study author Stam. M. Zervanos, an associate professor of biology at Penn State Berks–Lehigh Valley College.

“For males, these early excursions are an opportunity to survey their territories and to establish bonds with females,” Zervanos said in a statement then. “For females, it is an opportunity to bond with males and assess food availability.”

Zervanos conducted groundhog surveillance on 32 of the animals in Southeastern Pennsylvania over four hibernation seasons (two years), tracking their comings and goings with cameras strategically placed at the entrances to their burrows.

On average, the groundhogs he studied went into hibernation on Nov. 7 and woke up for good on Feb. 28. But the ladies apparently needed their beauty rest: They snoozed for an average 117 days, compared with the guys' 106 days of shut-eye.

In one case, when a male groundhog emerged from his den, he hung out for a few days at the entrance of the girls' dorm until one of the lasses came out, according to the Penn State write-up of the research. And then, like a typical guy, he went and visited another woman.

Image of Punxsutawney Phil/Alan Freed