"They can smell the fresh air and they can know it's warming up. They're probably very ready to go outside," said Joan Daniels, associate curator of mammals at Brookfield Zoo, brookfieldzoo.org. But are they ready to run?
"I'm sure they will," Daniels said.
If you happen to be there when the giraffes decide to run, it's a sight you'll remember all summer long. They've been inside for five months and with those long necks and long legs, cabin fever sets it in something fierce.
After the release, it's an adventure in ultra slow motion. But then the giraffes brush off their winter cobwebs and the four females and one male add a little spring to their steps.
"It seems like when one of the youngsters gets going ... and they start running everyone starts to follow. It's kind of a chain reaction," said Daniels.
Giraffes have one of the craziest body designs in the animal kingdom and when they run they seem to be coming and going all at the same time.
"I thought it was pretty cool," said Emilee Holzwarth, giraffe lover. "Because I've never seen a giraffe run before."
they don't appear to be running very fast -- but they are. And in the wild they can really fly.
"Speeds of up to 35 miles per hour. They can sustain that speed for a long time and lions in general can not sustain their speed that long," said Daniels.
And this spring fling was all over in just ten minutes-- and there's a good chance these giraffes won't all run again together until next spring.