Efforts to get two new tigers at Blijdorp zoo in Rotterdam to mate as part of a captive breeding programme have ended in tragedy, after a fight in which the female tiger died.

The tiger, known as Nonja, was found dead in the tiger enclosure on Friday morning. She had arrived in the zoo in June, three weeks after the Sumatran male Geram.

The two tigers were placed in the same enclosure on Thursday after Nonja appeared to be in heat. “That meeting ended in a fight,” the zoo said in a statement. “The zoo keepers eventually managed to separate the two animals.”

An autopsy at Utrecht University’s faculty of veterinary medicine showed Nonja had been killed by bleeding on one of her lungs, probably caused by a bite. The injury had not been visible through her thick coat, the zoo said.

There are just 350 Sumatran tigers, which live a solitary existence, in the wild.

The zoo said it did not yet know what impact the death would have on any future attempts to breed Sumatran tigers in Blijdorp.