Two brown bears that escaped from their enclosure at Whipsnade Zoo and attacked a boar have been put down over concerns of an "immediate threat to human life".
The pair made their way along a fallen tree which had come down in strong winds and formed a ‘bridge’ between their enclosure fence and the fence of the neighbouring wild boar section.
It was then that they attacked the male boar, injuring the animal, and bosses at the site near Dunstable, Bedfordshire, said they had no choice but to euthanise the two female bears. They were reportedly shot.
The zoo’s chief curator, Malcolm Fitzpatrick, said in a message to staff: "As brown bears are strong and dangerous predators, our first priority is safety.
"We must quickly make decisions informed by our experience and expertise to protect our people, guests and our other animals."
He said tranquilisers were not an option as they would have taken at least 20 minutes to work, "during which time the animals can become unpredictable and aggressive as adrenaline is coursing through them".
"That’s a risk we couldn’t take," he said. "We had to intervene immediately to ensure the bears didn’t get out of the boar enclosure, which has a low fence."
A third brown bear did not leave the enclosure, and was called to her indoor den and secured while the fallen tree was removed.
An investigation will take place into the incident, which happened on Friday morning.
Mr Fitzpatrick added: "As zookeepers and animal carers, this situation is something we train to deal with through regular, rigorous drills – but one that we always hope we’ll never have to face.
"I’m devastated by the outcome of this morning’s incident, but I’m confident that our actions prevented any further loss of life."
He explained: "Our experienced zookeepers, who were on the scene within minutes, promptly assessed the situation and agreed the only option was to euthanise the bears.
"No one wants to be the one to make that call, but when there’s an immediate threat to human life, the decision is made for you.
"The colleagues involved today have experienced the dreadful situation that every vet and keeper thoroughly trains for, but hopes will never come to pass.
"I ask you to support them in the coming weeks as they come to terms with today’s events."