Planning is considered to be a fundamental property of intelligent behavior, which begins with the thinking process that ultimately terminates in a goal. We know humans are capable of it, and this is probably one of the processes that characterize us the most, yet we are not the only ones who can think ahead.

A male chimp at the Furuvik Zoo in Lund, Sweden has had quite a habit for the past 10 years, which involves storing objects, and using them as missiles against visitors. According to scientists at the Lund University Cognitive Science, whose findings appear in Current Biology, the chimp’s planning actions took place in a calm state, and included stone caching and the manufacturing of discs from concrete. Throwing these objects at visitors later on took place in an agitated dominance display.

The chimp now has a daily routine of storing ammunition and using it against visitors. Such planning, scientists said, implies advanced consciousness and cognition which is not normally associated with nonhuman animals. Furthermore, spontaneous and unambiguous planning behaviors for future states by nonhumans have never been reported.

Dr. Mathias Osvath, cognitive scientist at the Lund University and author of the study, told BBC that they’ve done experimental studies, and chimps have clearly shown they plan for future needs, but it has also been argued that this was an experimental artifact. This spontaneous behavior however could be seen as evidence, he said.

Santino, the male chimp, has been with the zoo since 1983. His rock-throwing habit began over one decade ago, first with one stone thrown from time to time. However, the number of rocks used began to multiply. But things are more complex than that: Santino didn’t normally have access to so many stones, until the zookeepers found that he had been carefully stockpiling them.

“He is not driven by an immediate physical or psychological need … [but] … by an image of his future mental and psychological state,” Osvath said, according to the Scientific American. “He is extremely calm when collecting stones, and then becomes very agitated when throwing them.”

While we still don’t know if animals are capable of such behavior in the wild as well, Santino’s example goes to show that thinking ahead is not necessarily a human-exclusive behavior. The chimp would not only stockpile rocks, his actions must have been motivated by learning that the rocks would eventually end and he would need new ammunition.

The chimp also went from gathering rocks to fabricating his own ammunition (probably after seeing rocks were quite scarce in his enclosure). Scientists reported that Santino also began fabricating concrete discs to throw at visitors. The zookeepers have been trying hard over the years to take away his ammunition, yet the chimp always seemed to find more. No visitor ever got injured during Santino’s ‘attacks’.