Why people are warned against smiling into gorilla enclosures after woman faced horrific consequences

A day out at the zoo is usually always a good time.

You can have a look at some of the world's weirdest and most wonderful creatures, learn all about their behaviour and habits and bag yourself a pretty cool souvenir at the inevitable gift shop.

However, it's clear things don't always go to plan after one zoo visitor found out the hard way exactly why you should refrain from smiling into gorilla enclosures.

There's a terrifying reason why you should never smile at a gorilla in a zoo. (ullstein bild / Contributor / Getty Images)

It all started over a decade ago, back in 2007, when children reportedly started throwing rocks at the gorilla.

However, before this happened, a frequent attendee of the zoo had been regularly smiling and making eye contact towards the animal.

The gorilla, whose name was Bokito, then managed to break free from his enclosure after jumping out, leading the woman to be seriously injured at the Diergaarde Blijdorp zoo in Rotterdam.

Bokito then reportedly dragged the woman around before biting her and causing multiple fractures.

And it didn't stop there.

Bokito resided at the Diergaarde Blijdorp zoo in Rotterdam. (JERRY LAMPEN / Stringer / Getty Images)

The gorilla then went into a restaurant, where three more people were injured, before he was eventually sedated with a tranquilliser gun and taken back to his enclosure while the woman was rushed to hospital.

It was later reported that the woman had been visiting the gorilla on an average of four times a week since he was four months old and, in her regular visits, had a habit of making eye contact with Bokito and smiling at him - which her husband said she had been advised not to do by a zookeeper.

In an interview with newspaper De Telegraaf, the woman later said: "If I laugh at him, he laughs back."

The woman apparently visited Bokito since he was just a baby. (ED OUDENAARDEN / Stringer / Getty Images)

Well, it's clear doing so is a major no-no when it comes to zoo etiquette as Gorilla Trek says that making eye contact with a gorilla should be steered well clear of.

It explains: "To mountain gorillas, any person who keeps direct eye contact with them is a challenger and an enemy who comes to destroy the family.

"Direct eye contact will therefore force the silverback to charge and fight you in order to defend his family. If you want to be peaceful with gorillas, you should avoid eye contact."

Bokito was later tranquillised. (AFP / Stringer / Getty Images)

One person later shared their own experience with a similarly terrifying experience on Reddit.

They explained: "I once worked in a zoo on work experience at 15. I made the briefest of eye contact with a sliver back at the back feeding part of the enclosure, (not dissimilar to silence if the lambs prison, but with fencing) that was enough to of caused it to run at me and smash against the weak looking fencing with both fists and grunting heavily.

"He then grunt called to the others, who sloped off there platforms and started trying to get me with sticks and throw hay at me, I was quickly escorted out."

They continued: "It was prob because a cute baby gorilla was bashing its chest till it fell backwards and I was watching that, and the silver back was watching me in the background.

"They are very much not to be messed with and like pretty much all other animals, not to be imprisoned for our viewing curiosity."

Note to self: never smile at a gorilla.