George Leslie, a postdoctoral fellow at the School of Medicine, happened to pass by and took some pictures, one of which has been circulating on the Internet.
In the photo, the camel is lying down and several young women with drinks in plastic cup are standing next to him.
"It looked like a terrible scene," said Leslie, 42. "There was loud music and drunk college students everywhere."
Scott H. Reikofski, director of fraternity and sorority affairs, said he was investigating and hoped to have a resolution soon. The fraternity could not be reached for comment.
Matey said the fraternity had hired her animals for the last five years. Besides the camel, she brought goats and other farm animals for the petting zoo.
This year will be the last, she said tearfully over the phone Thursday night.
Matey said she feared that Penn students and employees who objected to the animals' presence on campus would try to ruin her business.
She said she is hired to take her animals to nursing homes, to visit autistic children, and to events such as the opening at the Franklin Institute.
She said she licensed as an exhibitor with the U.S. Department of Agriculture, which inspects her animals.
"If this camel were upset" with being at the party or being around the students, Matey said, "he would be growling and kicking and spitting, not lying down."
Contact staff writer Robert Moran at 215-854-5983 or email@example.com.