The adult male and two nearly eight-month-old pups got out of the enclosure at Mesker Park Zoo on Wednesday and were all caught again within an hour.
Officials first thought the wolves dug their way out, but zoo director Amos Morris tells the Evansville Courier & Press that the wolves worked apart some loose rings holding the chain-link fence together.
Morris says the zoo staff will continue reviewing the escape. He says zoo workers make daily checks of all animals and exhibits.
He says the zoo staffers did an excellent job corralling the 100-pound adult wolf and returning him to the exhibit.