For 38 years, Bengt Röken has worked with, among other things, chimpanzees at Kolmården outside Norrköping.

He knows the difficult position the animal keepers and veterinarians at Furuvik find themselves in.

When the chimpanzees escaped from their enclosure on Wednesday, he was contacted by the district veterinarian in Gävle for advisory purposes.

The first thing Bengt Röken learned then was that two of the three monkeys that first escaped had already been shot.

Which he thinks was a wise move.

When the remaining ones were to be captured, immobilization came into play, i.e. putting the animals to sleep.

- We discussed it and which doses to use in that case, but I still advised against it.

It is not a method suitable for this type of situation.

But it could have been solved in other ways, says Bengt Röken.

Easier to put lions and bears to sleep

In difficult situations, such as the one currently taking place in the monkey house, it is better to shoot than to try to sleep.

But in the end, that decision is made on the spot.

- Chimpanzees are intelligent animals and if they experience a threat from people who have stun guns, they hide.

Once they've spotted you, they won't take their eyes off you.

And if you manage to hit them, they are lightning quick to remove the arrow, he says.

According to Bengt Röken, chimpanzees are among the most difficult animals to put to sleep.

You only have one chance, he says.

- Only wolves on the run are more difficult.

It would be easier if it was a lion, tiger or bear.

They behave in a way that makes it easier for us to get close, says Bengt Röken.

Here shooters guard outside the monkey house at Furuviksparken: "High-risk animals":

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Here the weapon is pointed from the car at an open window in Furuviksparken.

Photo: Jan-Peter Eriksson/SVT