A chimp in The Netherlands took down a drone that was used in filming the Burgers' Zoo in April. Researchers have now published a quite impressive analysis of the clip in the journal Primates. Besides showing a stellar example of tool use, according to researchers the video has shown that the chimp planned out its actions.

The drone caught the attention of a number of chimps in the enclosure when it had flown by in a practice run. At that fly-by, many chimps grabbed twigs and climbed up towards where the drone was hovering.

When the drone returned, they were all set as two females were sitting where the drone was about to hover, with long twigs. Primatologists said that their faces showed exertion and no fear, indicating that they were acting intentionally. They were not flailing around in terror at the alien object.

In a statement, study author Jan van Hooff, a primatologist with life-long ties to the zoo, said, "The use of the stick as a weapon in this context was a unique action. It seemed deliberate, given the decision to collect it and carry it to a place where the drone might be attacked".

The impressive thing was the use of tools, keeping in mind that no humans have taught the captive chimps how to use tools. The chimps noticed human beings and came to learn how to use around 13 unique tools.