A female chimp at the Royal Burgers Zoo in Amhem, The Netherlands downed a drone using a long stick in April. As scientists examined the chimp's behavior, they discovered that it was not a random action but an intentional, planned action, according to The Washington Post.

The drone belonged to a Dutch TV crew that wanted to film the animals in the zoo and get up close shots of the chimps. However, as the study authors noted, the chimpanzees seemed to show a particular dislike toward the drone.

When the drone flew by for a practice run, the chimps could be seen picking up willow twigs as it passed above them. Some of the chimps, while still carrying the twigs, climbed the scaffolding near where the drone was flying, a behavior that was not usually observed among them, according to a press release.

When actual filming began, the drone flew above the chimps once more. As it went near two female chimps for a closer look, one of them suddenly whacked it with a 6-foot-long twig. After missing the drone on her first swing, she whacked the drone a second time and successfully brought it down.

The video - or what was left of it - showed the female chimp grimacing as it attempted to hit the drone. However, she did not show any sign of fear, indicating that the act of swinging the twig was a calculated move, and not just a random act, to use the twig as a tool in order to put the drone down.

"The use of the stick as a weapon in this context was a unique action," Jan van Hooff said in the press release. "It seemed deliberate, given the decision to collect it and carry it to a place where the drone might be attacked."

The authors said that the chimps in the zoo had not been taught how to use tools, but they had many opportunities to observe humans use various objects.

"This episode adds to the indications that chimpanzees engage in forward planning of tool-use acts," Bas Lukkenaar said.

The study was published in the Sept. 3 issue of the journal Primates.

See the video of the chimp below.