Meanwhile, the zoo's other groundhog, Cloudy, didn't even come out of hibernation to give winter a chance.
It's the second time in her three year career that Tumbleweed has predicted an early spring. Cloudy has been predicting since 2001.
During hibernation, a groundhog's body temperature drops to 38-degrees and it takes a breath about once a minute. Also, its heard slows to only four to six beats a minute. According to a release from Brookfield Zoo, after temperatures warm, groundhogs can take several hours to rouse from their slumbers and interrupting hibernation can interfere with their metabolism. Therefore, zookeepers will not force them to come out of hibernation before they're ready.
About 300 people were at Brookfield Zoo's Groundhog Day event.
