Courtesy Virginia Zoo

Rufus had been at the Virginia Zoo in Norfolk since 1974.

NORFOLK – An internal investigation is underway following the death of a white rhino at the Virginia Zoo.

An early investigation indicates Rufus, 36, and Alfred, 40, forcibly charged each other while inside their night house either Sunday night or early Monday morning.

Rufus apparently died of injuries from that incident.

Annie Vogt, Director of Communications and Development for the zoo, said a closing procedure for a gate wasn't followed and that allowed the two male rhinos to be in the enclosure together.

Vogt explained that male rhinos that aren't raised together fight, so while one would be on exhibit, the other would be behind the scenes and never together.

"A horrible mistake occurred. It was human error and we're all dealing with it," she said. "Animal safety is our top priority and that’s why we have these policies and procedures."

The zoo closed at 5:00 p.m. Sunday and Rufus was found early Monday, several hours before the zoo's normal 10:00 a.m. opening.

"The Association of Zoos and Aquariums won’t actually need to come on site for an inspection as this was an error in someone’s judgment. The USDA will inspect us and they have been notified," Vogt confirmed.

Rufus had been at the zoo since 1974 and was one many animals in the zoo's Africa exhibit.

Alfred remains on exhibit at the zoo and is eating normally, Vogt added.

In 2004, a 32-year-old female white rhinoceros died when it fell into a 10-foot moat after being chased by a zebra. That rhino was not replaced.

Vogt says it's too early to talk about replacing Rufus and for now, Alfred will be on exhibit.

“We’re committed to having the most vibrant zoo we can," Vogt stressed.