But in the end it was the bear who ended up fighting for his life after police shot it in order to save the life of the uninvited intruder into his enclosure.

These dramatic photographs were taken by a visitor to the Bern Park, Switzerland, on Sunday when Finn, a European brown bear aged four, suddenly realised the unwanted human guest in his home.

The 25-year-old man's bid to party with Finn mirrors a similar escapade in Berlin Zoo in Germany on Good Friday this year when Mandy Knobloch, 32, jumped in to swim with the polar bears.

She was severely mauled but rescued before keepers had to open fire on the bears.

Finn was not so lucky. As his massive jaws – capable of crushing steel – and eight-inch fangs that can rip flesh like paper sank into his prey, police had to act fast to save the life of his prey.

Finn picked up the intruder as if he were a rag doll, carting him to the other side of his enclosure which only opened last month.

He pounced after the man climbed onto a wall surrounding and jumped 20 feet into his home.

Police were left with little option but to open fire, they said. Yet they used a fragmentation bullet, the kind which splinters inside the target.

Finn is critically ill but veterinarians are unable to operate because of the number of splinters caused by the bullet.

The man sustained severe head and leg wounds but he is out of danger. Police and zoo officials say there has been an outpouring of public sympathy after the incident – for the bear.