One tiger killed another at the Toronto Zoo on Thursday, staff confirmed.

Brytne, a 13-year-old Sumatran tiger, was attacked by a three-year-old male tiger in the morning.

Though zookeepers intervened and separated the animals, it was too late. Brytne died of a crushed larynx.

Sumatran tigers are critically endangered. According to the Zoo, there are only about 300 to 500 of them left in the wild.

Harimau Kayu, the three-year-old, arrived in June from the San Diego Wild Animal Park on a breeding recommendation.

Previously, Brytne had given birth to two litters with another male.

For the past six month, the Zoo said, staff have been working to introduce the animals. They have been seen nuzzling and chuffing, an action similar to purring.

The Toronto Zoo is currently under fire from the city over the transfer of three elephants to a California sanctuary.

City council approved the decision to transfer the elephants to the Performing Animal Welfare Society (PAWS) in San Andreas in October but say the Toronto Zoo is deliberately stalling the move.