A team of researchers from Lund University in Sweden studying the behavior of Santino the chimpanzee at Furuvik Zoo in Stockholm has found that he uses innovative foresighted methods to fool zoo visitors.
Image shows Santino the chimpanzee when he slowly moved towards the group of visitors and picked up an apple from the water moat 15 seconds before releasing his projectiles, note two projectiles in his left hand (Tomas Persson)
Chimpanzee Santino achieved international fame in 2009 for his habit of gathering stones and manufacturing concrete projectiles to throw at visitors from the safety of his enclosure at Furuvik Zoo north of Stockholm.
His behavior was reported as an example of spontaneous planning for a future event, in which his psychological state was visibly quite different from that of his subsequent aggressive displays.
The new study, published in the journal PloS-ONE, shows that Santino not only gathers stones and manufactures projectiles in advance – he also finds innovative ways of fooling the visitors.
The behavior of the chimpanzee Santino is of particular interest because it is done while the humans to be deceived are out of sight. That means that the chimpanzee can plan without having immediate perceptual feedback of his goal – the visitors to the zoo – to aid in his planning. Previously, such cognitive abilities had been widely believed to be restricted to humans.
The team collected more detailed data on Santino’s projectile-throwing behavior over the course of the 2010 zoo season.
The chimpanzee continued and extended his previous behavior of caching projectiles for later use in aggressive throwing displays.
The new behavior involved innovative use of concealments: both naturally occurring ones and ones he manufactured from hay.
All were placed near the visitors’ area. This allowed Santino to throw his missiles before the crowd had time to back away. The first hay concealment was made after the zoo guide had repeatedly backed visitors away when the chimpanzee made throwing attempts.
All concealments were made when the visitors were out of sight, and the hidden projectiles were used when they returned. In order to make the hay concealments the chimpanzee had bring the hay from the inside enclosure.
Over the course of the season, the researchers observed that the use of concealments became the chimpanzees preferred strategy. Moreover, Santino combined two deception strategies consistently: hiding projectiles and inhibiting the displays of dominance that otherwise preceded his throws.
The findings suggest that chimpanzees may be able to represent the future behavior of others while those others are not present. It is also critical that the chimpanzee’s initial behavior produced a future event, rather than merely preparing for one that had reliably occurred before. This in turn, suggest a flexible planning ability which, in humans, relies on creative re-combining of memories, mentally acted out in a ‘what if’ future scenario.
