A female tiger was fatally mauled at the San Diego Zoo by a potential mate, officials confirmed Monday.
Tiga Tahun, a large Malayan female Tiger, was introduced to Connor on Saturday, and zoo staffers hoped it would be the beginning of a breeding process to help protect the endangered species.
But the zoo's staff said the interaction turned violent, and they were unable to separate the two tigers.
No visitors saw the attack.
Tiga Tahun died Saturday of neck injuries and breathing difficulties.
She was born in 2009 at the Bronx Zoo, but was owned by the Omaha Zoo.
Connor was born at the San Diego Zoo in 2011.
"Large carnivores often mix aggressive behavior with breeding interactions and this sometimes results in injury or death," zoo officials said in a statement.
In August, a rare set of Sumatra cubs were born successfully at the National Zoo in Washington, D.C.
The San Francisco Zoo also welcomed a new Sumatran tiger cub this year.
The San Diego Zoo Safari Park announced it was in the midst of a baby boom over the summer with babies available for park visitors to see.