1 Chimp + Many Rocks = Duck!

Whenever a study claims a “first”—as in the first evidence for this or that phenomenon—my suspicious side emerges. A fascinating paper in the March 9 issue of Current Biology describes what it calls the first unambiguous evidence that a non-human animal (in this case, a male chimpanzee who lives in Sweden’s Furuvik Zoo) can plan for future contingencies: for the last 11 years Santino, who is 30, has been regularly collecting stones from his enclosure in the early morning hours before the zoo opened, stockpiling them in groups of three to eight, and then hurling them at visitors later in the day.

Planning, sure. But the first evidence of that? As coincidence would have it, the same journal published a study last month describing how capuchin monkeys in the wild intently check out stones of various weights and sizes, compare them to one another, and then choose those that will serve as the best anvils and hammers. Capuchins, like some other wild primates, use tools and, as this study shows, form a mental image of what that future tool should look like. (Current Biology has, on its home page today, a charming video of the capuchins doing this.)

But back to Santino. As Mathias Osvath of Lund University reports, Santino began hurling stones across a moat at visitors in 1997, in what zoo officials infer was a dominance display. Curators did some sleuthing, and found that he had cached dozens of stones in his activity area. The curators removed them, but Santino just collected and stashed away more—those he found in the enclosure as well as chunks of concrete he knocked off walls and broke into smaller, more throw-able pieces. Over the years, they found hundreds of caches. Santino would throw the rocks underhanded across his moat at visitors (luckily, he has lousy aim).

Planning, yes. As Osvath put it, “These observations convincingly show that our fellow apes do consider the future in a very complex way. It implies that they have a highly developed consciousness, including life-like mental simulations of potential events. They most probably have an ‘inner world’ like we have when reviewing past episodes of our lives or thinking of days to come. When wild chimps collect stones or go out to war, they probably plan this in advance. I would guess that they plan much of their everyday behavior.”

But the first evidence of planning? Orvath argues that inspecting and collecting stones in the wild, to use for cracking nuts, may not truly represent planning. Instead, it may meet what he calls an immediate or current need rather than a future one. Santino’s collecting, in contrast, is not based on his “current drive state,” Orvath argues, since while collecting and caching stones he was calm but when throwing them he was extremely agitated.

But surely that same criterion could be applied to using stones in the wild. The capuchins who carefully consider the merits of various stones for anvils and hammers are projecting forward in time to when they will need them to crack nuts, no? If you want to claim that the capuchins’ “immediate need” is acquiring good tools, but their future need is food, then surely that same argument goes for Santino: his immediate need is to acquire weapons, which he satisfies by stashing rocks, and his future need is throwing them.

Osvath himself admits that “wild chimpanzees might be even better at planning as they probably rely on it for their daily survival. The environment in a zoo is far less complex than in a forest. Zoo chimps never have to encounter the dangers in the forest or live through periods of scarce food. Planning would prove its value in ‘real life’ much more than in a zoo.”

Anyway, it’s always a good idea to be cautious about claims of firsts.