Visitors at the Bronx Zoo were shocked when a gorilla started performing oral sex on its partner while they watched.

A clip of the gorilla pleasuring its partner in front of aghast zoo-goers is currently blowing up on social media after it was shared online.

As the gorillas began performing the sex act, mothers quickly turned their children’s faces away.

Reacting, animal experts say the gorilla’s behaviour is all completely normal.

The videographer who captured the incident while visiting the iconic NYC zoo with his family told The Post: ” I was shocked and had no idea that was a ‘natural’ act.

“I was in the gorilla exhibit with my 4-year-old daughter and niece. My wife had to stay out of the exhibit with my sleeping son, so I wanted to capture a lot of video. Then this magic happened.”

Watch the video below.