PITTSBURGH, Pennsylvania (Reuters) - An endangered female leopard put in a cage to breed was killed by her potential mate, who a day later remained on public display at the Erie Zoo, wildlife officials said on Tuesday.

The two Amur leopards, 5-year-old Edgar and 7-year-old Lina, were placed together in an enclosure at the western Pennsylvania zoo on Monday, said Erie Zoo president and CEO Scott Mitchell.

Edgar attacked Lina, biting her throat. The leopards were separated and veterinarians were brought in, but Lina died of injuries to her trachea.

Violence during mating is not unheard of, Mitchell said, but in his 30-year career he has never lost another zoo animal in a breeding attack.

"Many of these animals live their lives relatively solo, and they come together only to breed or mate, so it can be a kind of aggressive process," Mitchell said.

Lina, who was on loan from the Minnesota Zoo, had been placed together with Edgar in the past without incident, Mitchell said.

Edgar remains on display at the zoo, his future uncertain.

"He might move to a different facility, he could be part of an artificial insemination, we don't yet know," Mitchell said.

Amur leopards are among the most rare and endangered big cats, with about 40 of them living in the wild in China and Russia, and around 200 living in captivity worldwide, according to the Zoological Society of London.

(Reporting by Elizabeth Daley; Editing by Barbara Goldberg and Gunna Dickson)