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Chimp Santino Plans His Attacks on Zoo Visitors


Santino has never had much patience for the humans who come to gawp at him at the Furuvik Zoo in Sweden. Fifteen years ago, at age 12, he began picking up stones, storing them for future use, and hurling them at visitors.

But his war on his captors has been escalating and has reached new levels of sophistication. And scientists are fascinated by his latest tactics. His capacity for careful planning puts another nail in the coffin of old theories that insist that humans are the only species capable of such cognitive games.

A team from Lund University in Sweden spent four months observing Santino at the zoo and documenting the level of strategic planning and complex tactics that he’s been developing. In their latest report, they say that Santino demonstrates particular cunning when it comes to finding ways to fool the visitors.

During the night, Santino carefully places his projectiles under piles of hay near the visitors’ viewing area. His arsenal consists of stones and concrete discs he takes from his ornamental lake.

Then, the following day, he sits around nonchalantly within a proverbial stone’s throw of his audience, and then, usually about lunchtime, his patience seems to run out as he grabs the stones and hurls them at the onlookers.

Mathias Osvath, who led the research team, shows some of Santino’s favorite hiding spots

While Santino’s apparent tantrums are a definite hazard to visitors, they are fascinating to primatologists Mathias Osvath and Elin Karvonen. That’s because they demonstrate a high level of advance planning – “a cognitive process generally viewed as uniquely human.”

In a separate article entitled “Spontaneous innovation for future deception in a male chimpanzee” in the journal PLoS One, Osvath and Karvonen argue that because Santino hid stones and then tried to deceive zoo visitors into thinking his intentions were peaceful, he was anticipating or planning for a future situation rather than responding repetitively to a past one. This indicates that the chimpanzee can recombine memories, mentally acting out a “what if” future scenario – a cognitive ability that has long been thought to be unique to humans.

In his earlier study, reported in Current Biology, Osvath wrote:

The chimpanzee has without exception been calm during gathering or manufacturing of the ammunition, in contrast to the typically aroused state during displays.

The gathering and manufacturing has only been observed during the hours before the zoo opened, excluding potential triggering from the presence of zoo visitors. The delay between the gathering and the throwing of the stones is typically several hours. The chimpanzee has not been observed using stones or concrete in contexts other than throwing, and the behaviors have not been exhibited off-season when the zoo is closed and visitors are absent (50% of the yearly outdoor period is off-season).

The purpose of the behaviors is further demonstrated by the fact that the discovered caches were always located at the shoreline facing the visitors area; representing less than 25% of the island’s circumference.

Santino has put some hay near where the visitors stand and has cached
a stone under it and out of sight of the visitors. (It’s just visible in the front.)

The new findings suggest that chimpanzees can formulate in their own minds the future behavior of others while those others are not present. The researchers also note that this behavior suggests a flexible planning ability which, in humans, relies on creative re-combining of memories, mentally acted out in a ‘what if’ future scenario. The authors write:

The results suggest that the chimpanzee crafted a desired outcome in a perceptually detached future by acting innovatively in his current situation. Such activity produces a specific future event, in contrast to activity that merely prepares for a future situation as repetition of a previously experienced event.

That is why the most critical finding of this study is the observation of the first instance of the concealment behavior. This is indication of the existence of that type of perceptual simulation used by humans in certain planning tasks: a recombining of components of previously experienced events. The data further show that chimpanzees are able to plan for social situations – at least for deception – and that social planning in general is not out of reach for chimpanzees.

While it’s normal for chimpanzees to show signs of aggression toward each other and toward visitors as a display of dominance, it looks like Santino simply “finds it fun” to annoy humans. He even appears to target certain people who get on his nerves.

Osvath says the chimp is showing us something very fundamental about chimps.

“What makes this a bit special,” he said, “is that he actually had not experienced before what he seemed to anticipate. He, in a sense, produced a future outcome instead of just preparing for a scenario that had previously been re-occurring reliably.”

This mixture of previous experiences coupled with innovation, he said, “is a good sign of the rather sophisticated foresight abilities in chimps.”