Footage of a group of angry chimpanzees brawling at an LA zoo has gone viral.
The two-minute clip, posted on YouTube, shows the apes screaming and beating each other. One is chased into a ravine at what is thought to be Los Angeles Zoo and Botanical Gardens.
At the end of the video, one increasingly aggressive chimp picks up a big stick and uses it to attack another.
It is not known when the incident took place.
The footage, which has been shared hundreds of thousands of times, has provoked a huge response from the online community.
"This was one of the most entertaining things I have ever watched, lol," one viewer said.
Another commentator blamed the animal's behaviour on their conditions. "Zoos are jails; they drive them crazy. Stop zoos, free animals."
"You've got to wonder how much of this is just driven by the crowd response ... apes watching apes" one critic added.
The chimpanzee colony at the zoo, now numbering 15, is one of the largest in the US.
It is common practice at the zoo that keepers do not intervene when chimpanzees fight. This procaution is put in place to protect staff as the chimps are much stronger than humans, despite their lower average weight.
A spokesman for the LA Zoo told IBTimes UK that the behaviour of their chimpanzees are under constant monitoring.
"One of the rewarding aspects of managing a large troop of chimpanzees is the variety of behaviors and activities of the troop. Part of the natural behavior of chimpanzees is dominance, displacement and fighting," he said.
"While this video certainly shows disagreements and fighting, if you were to videotape our chimpanzees throughout the day you would see that this is just a fraction of the many behaviors they exhibit at the L.A. Zoo. Finally, our Great Ape Team (Curators & Keepers) constantly monitor the behavior of our chimpanzees."