Remember the chimp at a Dutch zoo who emphatically swatted a TV crew's drone out of the sky with a tree branch? Researchers who dissected Tushi's actions have concluded she planned the attack, sort of like a human would. 
 
 In a study recently published in the journal Primates, Jan van Hooff and Bas Lukkenaar re-examine the events of April 10, when a Dutch TV crew was using a camera-equipped drone to film a documentary of chimpanzees at a 1.7-acre enclosure at the Royal Burgers Zoo in Arnhem. 
 
 Some of the chimps grabbed branches or twigs from willow trees and two females, Tushi and Raime, climbed up on scaffolding. 
 
 As the drone got close, Tushi swatted at it twice with a 6-foot-long branch she brandished in her left hand. The second swipe made contact, knocking the drone to the ground. The camera continued to film, capturing the inquisitive faces of the chimps as they inspected and toyed with the perplexing gadget. 
 
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 The study's authors note that Tushi grimaces just before and during the act of striking. "The precise coincidence of the facial grimace with the strike suggests that it is a concomitant of an assertive and determined exertion of force, homologous to what humans do in comparable situations." 
 
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 The researchers note that Tushi collected the stick before the drone approached, and carried it to a place where the drone might be swatted. The sequence of events, they say, suggests the attack was "planned" and "deliberate." 
 
 "This episode adds to the indications that chimpanzees engage in forward planning of tool-use acts," they write. ||||| Incident shows that chimps are able to plan ahead and use tools as weapons 
 
 New York | Heidelberg, 3 September 2015 
 
 Cool. Calm. And oh, so calculated. That’s how a chimpanzee living in the Royal Burgers’ Zoo in the Netherlands set out to swat an aerial drone that was filming her group. In an article in the journal Primates published by Springer, Jan van Hooff and Bas Lukkenaar explain it as yet another example of chimpanzees’ make-do attitude to using whatever is on hand as tools. 
 
 
 
 
 
 The incident happened earlier this year, on 10 April, when a Dutch television crew was filming at the zoo in Arnhem. The idea was to use a drone to film the chimpanzees in their compound from different close-up angles. The drone already caught the chimpanzees’ attention during a practice run. Some grabbed willow twigs off the ground, while four animals took these along when they climbed up scaffolding where the drone was hovering. This behavior is not frequently observed among these chimps. 
 
 
 
 
 
 Filming started when the next drone flew over. It zoomed in on two chimpanzees, the females Tushi and Raimee. They were still seated on the scaffolding holding on to twigs that were about 180 cm (ca. six feet) long. Tushi made two long sweeps with hers – the second was successful in downing the drone and ultimately broke it. Before and during the strike, she grimaced. Although her face was tense and her teeth were bared, she showed no signs of fear. This suggests that she quite deliberately and forcefully struck at the drone, rather than fearfully or reflexively. 
 
 
 
 
 
 “The use of the stick as a weapon in this context was a unique action,” comments van Hooff. “It seemed deliberate, given the decision to collect it and carry it to a place where the drone might be attacked.” 
 
 
 
 
 
 “This episode adds to the indications that chimpanzees engage in forward planning of tool-use acts,” Lukkenaar says, explaining the broader significance of the filmed event. This incident also shows the apes cautiously inspecting the contraption and even throwing it around before they lose interest in it. 
 
 
 
 
 
 According to van Hooff and Lukkenaar, the chimpanzees housed at the Royal Burgers Zoo have never explicitly been taught how to use different tools, but have had ample chance to watch humans handle all kinds of implements. Previous studies showed that the chimps at this Dutch zoo spontaneously and innovatively use up to 13 types of tools in a variety of ways, especially utilizing sticks of different sizes. The apes appear to choose the size, shape and weight of the tools with a particular use in mind. Sticks are, for instance, used to gather fresh leaves from overhead branches, while heavy pieces of wood and stones are chosen as throwing weapons. 
 
 
 
 
 
 
 
 References: 
 
 1. Van Hooff, J.A.R.A.M. & Lukkenaar, B. (2015). Captive chimpanzee takes down a drone: tool use toward a flying object, Primates. DOI 10.1007/s10329-015-0482-2 
 
 2. Primates is the official journal of the Japan Monkey Centre. 
 
 3. The article has been made freely available online for everyone under the Springer Open Choice program. 
 
 Caption: 
 
 A female chimpanzee named Tushi uses a stick to “attack” the drone. Behind her Raimee is sitting also with a long stick | © Royal Burger’s Zoo 
 
 Further Information 
 
 About the journal Primates 
 
 About the Japan Monkey Centre 
 
 Services for Journalists 
 
 The full-text article, photos and a video are available to journalists on request. 
 
 Contact 
 
 Katrin Petermann | Springer | Corporate Communications 
 
 tel +49-6221-487-8414 | katrin.petermann2@springer.com
– A chimpanzee that famously knocked a flying drone out of the air with a stick earlier this year wasn't reacting out of fear or annoyance but rather executing a pre-planned and deliberate attack. That's according to a new study in Primates. "This episode adds to the indications that chimpanzees engage in forward planning of tool-use acts," researcher Bas Lukkenaar says in a press release. The Christian Science Monitor reports a Dutch TV crew was using the drone to film a documentary on the chimps at the Royal Burgers' Zoo in April. After a test-run with the drone, the chimps started collecting sticks and climbing scaffolding. When the drone returned, a chimp named Tushi was ready, swiping it out of the air with a 6-foot branch. While studying footage from the busted drone, researchers focused on Tushi's facial expression during the attack, NBC News reports. They found the grimace she makes before and during the incident is similar to what humans do while carrying out a predetermined use of force. According to the press release, the lack of fear in Tushi's expression means she wasn't simply attacking out of reflex. The Monitor explains it's the difference between a calculated plan and swatting at a mosquito. This isn't unusual behavior for the chimps at Burgers' Zoo; they've taught themselves to use 13 different types of tools, the press release states. (Now find out how chimps are more advanced than humans.)