Are We Smart Enough to Know How Smart Animals Are?(55)

To understand how others relate to one another is a basic social skill that is even more important for group-living animals. They deal with a far greater variety than the siamang. In a baboon or macaque troop, for example, a female’s rank in the hierarchy is almost entirely decided by the family from which she hails. Owing to a tight network of friends and kin, no female escapes the rules of the matrilineal order according to which daughters born to high-ranking mothers will themselves become high-ranking, while daughters from families at the bottom will also end up at the bottom. As soon as one female attacks another, third parties move in to defend one or the other so as to reinforce the existing kinship system. The youngest members of the top families know this all too well. Born with a silver spoon in their mouth, they freely provoke fights with everyone around, knowing that even the biggest, meanest female of a lower clan will not be allowed to assert herself against them. The youngster’s screams will mobilize her powerful mother and sisters. In fact, it has been shown that screams sound different depending on the kind of opponent a monkey confronts. Thus, it is immediately clear to the entire troop whether a noisy fight fits or violates the established order.17

The social knowledge of wild monkeys has been tested by playing the distress calls of a juvenile from a loudspeaker hidden in the bushes at a moment when the juvenile itself is out of sight. Hearing this sound, nearby adults not only look in the direction of the speaker but also peek at the juvenile’s mother. They recognize the juvenile’s voice and seem to connect it with its mother, perhaps wondering what she is going to do about the trouble her offspring is in.18 The same sort of social knowledge can be seen at more spontaneous moments, when a juvenile female picks up an infant that is unsteadily walking about, only to carry it back to its mother, which means that she knows which female the infant belongs to.

In white-faced capuchin monkeys, the American anthropologist Susan Perry analyzed how individuals form coalitions during fights. Having followed these hyperactive monkeys for over two decades, Susan knows them all by name and life history. During a visit to her field site in Costa Rica, I saw the characteristic coalition stance firsthand. Known as the overlord, two monkeys threaten a third with stares and wide-open mouths, one leaning on top of the other. Their opponent thus faces an intimidating display of two monkeys wrapped into one, with both threatening heads stacked on top of each other. Comparing these coalitions with known social ties, Susan found that capuchins preferentially recruit friends who are dominant over their opponent. This by itself is rather logical, but she also found that instead of seeking the support of their best buddies, they specifically recruit those who are closer to themselves than to their opponent. They seem to realize that there is no point appealing to their opponent’s buddies. This tactic, too, requires triadic awareness.19



Two white-faced capuchin monkeys adopt an “overlord” position, so that their adversary is confronted by two threatening faces and sets of teeth at once.

Capuchins solicit support by abruptly jerking their heads back and forth between a potential supporter and their adversary, a behavior known as headflagging, which is also used against danger, such as a snake. In fact, these monkeys threaten everything they don’t like, a tendency sometimes used to manipulate attention. Susan once observed the following deceptive sequence:

Pursued by a coalition of three higher-ranking males, Guapo suddenly stopped in his tracks and began to produce frantic snake alarm calls while looking at the ground. I was standing by him and could plainly see that there was nothing there but bare ground. He headflagged to Curmudgeon [one of his enemies] for support against the imaginary snake. Guapo’s pursuers stopped short and stood up on their hind legs to see if there was a snake. After cautious inspection, they once again began threatening Guapo. Switching tactics he glanced up at a passing magpie jay (a nonmenacing bird) and did three bird alarms in rapid succession—calls that are usually reserved for large raptors and owls. Guapo’s opponents looked up, saw that it was not a dangerous bird, and again resumed threatening Guapo. He reverted to the snake alarm call tactic once again vehemently bouncing at the bare patch of ground, threatening the “snake” vocally. Although Curmudgeon continued to glare at Guapo for a bit longer, the rest of the group stopped threatening him, and he was able to resume foraging for insects, moving slowly and nonchalantly towards Curmudgeon while occasionally casting a furtive glance in his direction.20

While such observations suggest but cannot prove high intelligence, there is an urgent need for information on the cognition of wild primates. Fieldworkers are finding ingenious ways to collect it. In Budongo Forest, in Uganda, for example, Katie Slocombe and Klaus Zuberbühler set out to record the screams of chimpanzees under threat or attack. These loud vocalizations serve to recruit aid, which prompted the scientists to see if the acoustics of screams depend on the audience. Given the dispersed lives of wild chimpanzees, only individuals who are within earshot—the audience—are likely to provide aid to a screaming victim. In addition to finding that the intensity of the calls reflected the intensity of the attack, the scientists noted a subtle deception encoded in them. Chimpanzee victims apparently exaggerate their screams (making the attack sound more severe than it truly is), provided their audience includes individuals that outrank their attacker. In other words, whenever the big bosses are around, chimp victims scream bloody murder. Their vocal distortion of the truth suggests precise knowledge of their opponent’s status relative to everyone else.21