A wild 'pirate' monkey climbed onto a boat to attack tourists.

The primates seemed to have learned how to spot passing vessels and target them for food along a river in Kanchanaburi, Thailand.

Footage shows a pair of macaques wading in the water as panicked tourists screamed in the tiny ship on March 29.

One of the creatures successfully boarded and grabbed a banana which it quickly stuffed into its mouth.

Holidaymaker Noy Schori said: ‘We didn't know what to do. No one expected that the monkeys would be that aggressive. It was an unforgettable trip for us.'

The group's guide was seen holding a blue pipe which he used to scare the primate away but didn't leave until it could steal fruit.

After munching on a banana, it quickly took the plastic bag where more food was placed and jumped out of the boat.

Some tourists laughed while a woman was seen shouting in horror at the sight of the thieving monkey.

Noy added: ‘It was scary and funny at the same time. The animal didn't hurt us. Maybe it was just hungry but still, we were surprised that it chased our boat.'