MADISON, Wis. -

The buses were barely on the streets when the phones calls started coming in to the administration offices of Madison Metro Transit.

The buses carry an advertising message, which is not unusual. But the buses in question feature an ad paid for by People for the Ethical Treatment of Animals.

The ad includes a photo of the face of a cat that appears to be part of a lab experiment. In bold letters it says, “I am not lab equipment!” It goes on to say, “End UW cat experiments."

“We’ve gotten some concerns that have been called into us already and we do understand those concerns,” Mick Rusch, spokesperson for Metro Transit, said. “We actually tried to work with that organization for a couple of months now trying to find something that would be a little more acceptable to Madison and unfortunately after several lengthy discussions we were unsuccessful in finding an alternative image.”

PETA paid to have the ads on Metro Transit buses for an eight-week period.

While overall bus advertising contributes roughly $400,000 a year to the Metro Transit budget, they say this is not advertising revenue they were seeking.

“It wasn’t about us looking to make a quick buck. This was us honoring our legal obligation under the First Amendment,” Rusch said.

He said their policy does allow them to reject advertisements from cigarette companies and anything deemed to be obscene, libelous or fraudulent. But he said attorneys for Metro Transit determined this did to not fall into those categories.

“The policy basically protects freedom of speech,” Rusch said.

He said Metro Transit plans to review their policy and look into what practices other transit organization use to deal with similar problems.