Stone-throwing Santino the chimp shows apes can carry out plans
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A chimpanzee named Santino has shown researchers that the great apes can plan ahead and execute carefully plotted maneuvers. Santino, the alpha male chimp at Sweden’s Furuvik Zoo, planned rock-throwing attacks against zoo visitors, which shocked zoo staff and fascinated scientists.
Writing in the journal Current Biology, Lund University doctoral student Mathias Osvath explains how Santino prepared an arsenal of rocks before the zoo opened, then waited until midday before throwing them at zoo-goers watching him across a moat around his enclosure.
‘These observations convincingly show that our fellow apes do consider the future in a very complex way,’ Osvath said of his research, which included both his own observations of Santino and interviews with three caretakers who’d worked with the chimp for 10 years. The Associated Press reports:
Seemingly at ease with his position as leader of the group, Santino didn’t attack the other chimpanzees, Osvath told The Associated Press. The attacks were only directed at humans viewing the apes across the moat surrounding the island compound where they were held. However, he rarely hit visitors because of his poor aim, and no one was seriously injured in the cases when he did, Osvath said.
Before his attacks, Santino had been observed tapping on concrete boulders to find weak areas where pieces could be easily broken off; if a piece was too large to throw, the chimp would break it into smaller pieces.
A 2006 staged experiment by scientists at the Max Planck Institute for Evolutionary Anthropology in Germany showed similar planning abilities in orangutans and bonobos. From the Associated Press:
In that case orangutans and bonobos were able to figure out which tool would work in an effort to retrieve grapes and were able to remember to bring that tool along hours later. ‘Every time you can combine experimental and observational data and you get a consistent result, that is very powerful,’ said an author of the 2006 study, Joseph Call. ‘This is an important observation.’ He noted that individual differences are big among chimpanzees so the observation might not mean all chimpanzees are capable of the same planning. ‘It could be that he is a genius, only more research will tell. On the other hand our research showed the same in orangutans and bonobos so he is not alone,’ Call said.
The Furuvik Zoo has gone to some lengths to stop Santino’s attacks on visitors. ‘Sometimes they will keep him in during the morning, and only let him out once the visitors have arrived,’ Osvath told the New Scientist. ‘It’s very hard to stop him because he can always find new stones, and if he can’t find them he manufactures them. It’s an ongoing cold war.’
Finally, the zoo decided to neuter the chimp in an attempt to curb his aggressive behavior. The surgery was performed late last year, but staff won’t know if it’s succeeded in calming him until the summer months, which is when Santino normally exhibits his rock-throwing behavior.
--Lindsay Barnett