A worker at a zoo in Tenerife is in serious condition in hospital after being shot with enough tranquiliser to take down a 400 pound gorilla.

The Loro Parque employee was dressed in a gorilla costume as part of a practice drill to simulate the escape of a captive gorilla when he was shot in the leg with the high-dose dart.

It seems not everyone had been informed that a drill was taking place and when a zoo vet saw the "gorilla" running through the park, he thought an actual gorilla had escaped and took action.

The worker had a severe allergic reaction to the tranquiliser and was taken to hospital.

Drills like this happen regularly at zoos but this is the first report of an incident of this kind. The zoo said that the vet had only been working there for two months.

Come on , people - when you're pretending a giant gorilla has escaped, it's probably best to make sure everyone know it's NOT A REAL GORILLA.

[Hat Tip: The Dodo]