A grumpy gorilla made his feelings clear about being filmed on camera by swiftly lobbing a small rock at a guest in Berlin Zoo.
Stefan Nolan, from Cork in Ireland, and his friends paid a visit to the zoo to kill time before their flight back and he got more than he expected while pointing his camera at a silverback gorilla.
The University of Limerick law graduate was recording the gorilla walking across the enclosure before it paused briefly to pick up a rock from the floor on 17 November.
As Stefan rushed to another spot to get a closer look, the gorilla quickly stood on its hind legs and chucked the rock hidden in his hand towards the onlookers with a small twig hanging between his lips.
Stefan later tweeted that the mischievous 26-year-old captive-born gorilla, who is called Ivo and is the only male in a colony of five, also tossed a massive clump of soil at another visitor before "running away".
The short 23-second clip has been viewed more than 170,000 times on YouTube.
In the caption, Stefan joked: "Apparently gorillas aren't a fan of the Irish."
The Zoologischer Garten Berlin received its first gorilla - a female called Fatou - in 1959.
Fatou, who is 57 and was born in the wild, gave birth to a baby in 1974 and still lives in the zoo in a separate enclosure.
M'Penzi, 29, Bibi, 17, and Djambala, 13, are three other female silverback lowland gorillas living at the zoo.Reuse content