Footage of a gorilla walking upright like a human at a Kent animal park has become a hit on YouTube, with more than 250,000 views in the past few days.
The 18-second clip of the 20-year-old Silverback gorilla shows him walking at Port Lympne Wild Animal Park, near Hythe, on his hind legs.
The male, called Ambam, is part of a bachelor group of critically endangered Western Lowland gorillas.
Keeper Phil Ridges said he was quite a celebrity at the park.
The footage was filmed by Animal Researcher Johanna Watson while she was working for a project on great ape locomotion.
Mr Ridges said Ambam was the park's biggest gorilla, weighing about 220kg (34 stone).
"Ambam's father Bitam used to display the same behaviour if he had handfuls of food to carry," he said.
He said both his sisters could also sometimes stand and walk in the same way.
"All gorillas can do it to some extent but we haven't got any who do it like Ambam and he is quite a celebrity at the park.
"We think he might use it to get a height advantage to look over the wall when keepers come to feed him and standing up can also help him in looking for food generally in his enclosure as it gives him a better vantage point.
"Ambam can also carry a lot more food if he stands and uses both hands and walking on two feet also means he doesn't get his hands wet when it is raining."