From Christophe Courteau's point of view, when the large mountain gorilla cocked its arm and clenched its fist and gave him the most ominous kind of look, it must have seemed as though the lights would be going out very quickly.
Making matters worse was that the alpha-male gorilla, normally timid in the presence of humans, was drunk on fermented bamboo stems–and ornery.
But the 46-year-old wildlife photographer, who captured the moments before physical contact was made, somehow emerged from the fracas with only a cut to his forehead.
The harrowing scene played out on the forested slopes of the Virunga Mountains, within Volcanoes National Park in Rwanda.
Caters News reports that Courteau, 46, was with clients photographing the well-known Kwitonda Group of silverback gorillas, including the alpha male, Akarevuro.
"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," Courteau said. "Suddenly, Akarevuro, who was [standing] 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."
Akarevuro weighs about 550 pounds, so this was a potentially deadly encounter.
But it turned out that the gorilla was not after Courteau, but a nearby male gorilla that that expressed interest in one of the Akarevuro's females.
"He did not care about me, and pushed me out of the way with his left hand as though I was not there," the photographer recalled. "Then he dashed through the vegetation to chase away a black-back male behind us."
This incident occurred at a time when mountain gorillas graze voraciously on bamboo shoots. The fermenting process occurs after the primates have ingested the woody grass.
The result is a state of drunkenness for gorillas that consume too much, followed by bouts of aggression or excitability.
Said Courteau: "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."
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