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"This is crazy. They can't catch them," laughed one witness in a video uploaded to Twitter.

The zebras' day in the city ended just before 3 p.m. when they were both recaptured unharmed, according to PhillyFireNews.com.

"Wild animals in circuses, that's expected to happen. You can't control wild animals," said Jackie Cane with Animal Activists of Philadelphia.

The circus says it is trying to figure out how the animals escaped.