Kansas City Zoo director Randy Wisthoff said an eastern black rhinoceros named Kipenzi died of an unspecified illness while being taken to the Oregon Zoo in Portland, Ore., where the animal was supposed to take part in a breeding program, the Kansas City (Mo.) Star said Wednesday.

"This is truly a devastating loss," Wisthoff said. "We are so committed to black rhino reproduction ... losing one to any reason is something that upsets us greatly."

Wisthoff said while the 8-year-old animal appeared normal when the transport began Saturday, it began acting violently Monday before finally collapsing in its transport cage.

Transporters took the ailing animal to the Phoenix Zoo, where Kipenzi died Monday night.