Lions and tigers and scares... oh my! For tonight's episode (9/8c, Syfy), Ghost Hunters heads to the Philadelphia Zoo to see if there's something even wilder than critters residing in the 42-acre landmark. "This is our first chance to investigate a zoo," says TAPS' lead investigator Jason Hawes. "And to do it at the first zoo in America is great." Still, the site's history had Hawes' partner-in-paranormality Grant Wilson feeling a little cagey. "It's supposedly a Native American burial ground. William Penn's grandson had a house here, it's been a zoo forever...it could be totally different hauntings than we're used to."