A photographer got a shot he wasn’t expecting while filming silverback gorillas in Rwanda when a 250kg ape – drunk on bamboo shoots – charged at him ‘like a rugby player’.

This incredible image shows the moment just before a drunken gorilla lashed out and punched a photographer.

Wildlife photographer Christophe Courteau was photographing a group of silverback gorillas in the forest of the Volcanoes National Park in Rwanda, when the alpha male of the family charged at him unexpectedly.

In a scene reminiscent of a bar brawl, the 250kg mountain gorilla, named Akarevuro, appears to clench his fist tightly before aggressively tackling the photographer.

Remarkably, Courteau managed to capture the gorilla on camera moments before the attack on the slopes of the Virunga Mountains.

Akarevuro was drunk from eating bamboo stems, which ferment in gorillas’ stomachs causing them to become intoxicated.

The primate is said to have felt threatened by a rival male, making him become excitable and defensive of his territory.

Courteau said: “I was taking photos of the gorilla family on the slopes of the Virunga Mountains with several clients of mine.

“We were all mostly focusing on a silverback called Akarevuro, the leader of the Kwitonda Group.

“All the members of this family were quite excited on this day, probably due to the consumption of the bamboo stems, which cause the gorillas to become extremely drunk and excitable.

“Suddenly, Akarevuro, who was stood close to us, just ran at me, but I could not move away as I was taking photos on my knees.

“In less than a second, he was on me, and strongly hit me like a rugby player.

“With the shock, I felt all his power and weight on my body. “A silverback gorilla like him weights around 250kg, so imagine a 250kg rugby player running straight towards you.

“Normally, they timidly avoid visitors when they move close, but not this time; Akarevuro was too excited and drunk. “He did not care about me, and pushed me out the way with his left hand like if I was not there.

“Then he dashed through the vegetation to chase away a black back male behind us who looked to be interested in one of Akarevuro’s females.” Remarkably, despite a small scar on his forehead, Christophe did not sustain any serious injuries from the incident.

He says that mountain gorillas are usually quite placid, only attacking strangers when they feel threatened or scared. However, when drunk on bamboo stems, they have a tendency to be excitable and belligerent.

During the rainy season, which is from October to November, mountain gorillas migrate to the slopes of the Virunga Volcanoes, where they graze on bamboo, a rich source of protein, which is plentiful in the area.

Dominant males, such as Akarevuro, are known to often consume the bamboo stems in vast quantities during this period, making them rowdy and hostile. When in their stomach, the bamboo undergoes a process called fermentation, thereby transforming the fibres in alcohol, making the gorillas completely drunk if they eat too much.

“The gorillas are just mad about the bamboos at this time of the year, stems and roots,” Courteau said.  “The problem is, when the gorillas eat too much of these bamboos, there’s a side effect: fermentation.

“And they often do so, especially the big males like the silverbacks, the dominant males. “I was not seriously injured in the altercation; I just got a souvenir scar on my forehead. “But I will remember this instant all my life long, it was like being hit by a train.”