Chimps are aggressive; bonobos are peaceful. Chimps often move in all-male groups, bonobos almost always in mixed groups. Chimps commit infanticide; bonobos don’t. Chimps use tools; bonobos, for all their intelligence, don’t. Female chimps are sexually available only in estrus; female bonobos are available any time. Bonobos favor the missionary position; chimps do it doggy style. And so on.
All these differences may come from a very simple niche distinction—the one I referred to at the beginning of this chapter, maybe the only new one in the whole chimp-bonobo history. Where bonobos live, edible plants abound on the ground, and bonobos snack on them while doing their serious foraging. Where chimps live, there are no plants of this kind. (If you want to know how all these consequences could follow from such a simple and seemingly trivial fact, read work by Frans de Waal or Richard Wrangham—it’s fascinating, though it’s got nothing to do with language.)
So was our last common ancestor more like a chimpanzee or more like a bonobo? You will actually see this debated on political lines—conservatives for chimps, liberals for bonobos. That’s ridiculous, of course: first because you can’t cherry-pick your ancestors, and second because the last common ancestor could have been at least as different from both chimps and bonobos as they are from each other.
At the same time, there are deep behavioral similarities between chimps and bonobos, most of which sharply differentiate them from our ancestors as well as from us. They both mostly inhabit deep tropical rain forests (though some chimps seem to thrive on the fringes). They both live mainly on fruit and nuts. They hunt and eat meat sporadically (chimps more than bonobos). They apparently never scavenge. And, despite their intense sociality and their talents when trained, they have no trace of language.
In the days of the common ancestor, forests stretched across central Africa from coast to coast, and the ancestral species, we may assume, roamed far and wide. Then seven or eight million years ago the climate began to change; paleoclimatologists have several theories why, but they needn’t concern us here. The Congo basin and the rest of lowland West Africa remained mostly wet and forested, but the eastern side of the continent grew progressively drier. It did not, as some outdated accounts suggest, turn into savanna overnight. The drying trend (interrupted by pluvials, long phases of increased rainfall) extended over millions of years. Unbroken forest gradually gave way to a mosaic of forest remnants, scattered woodlands, and grass. And in response to the loss of Eden came species that could survive in this strange new scenery—australopithecines, the “southern apes” (so called not because there was anything especially southern about them, but because the first one to be discovered, by a South African, Raymond Dart, happened to lie on his home turf).
Australopithecines came in two brands, each with assorted flavors, and it’s unlikely we’ve yet heard the end of the arguments about who they were, how many of them there were, which was which, and which, if any, gave birth to the first species that we dignify with the prefix Homo. (In idle moments I like to wonder whether an alien paleontologist from some species quite unlike ours would analyze and divide the fossil bones the same way we do—a fruitless exercise in itself, but it helps remind us of the inevitable subjectivity latent in any research that we conduct on ourselves.)
The two brands are known as gracile and robust—the gracile were relatively slight and skinny, the robust stockier. One of the few things paleontologists agree on is that the robust ones had nothing to do with us. They had big teeth adapted for eating uncooked tubers, and presumably they went around with digging sticks digging them up. The last of them died out around a million years ago. Maybe they ran out of tubers, maybe our ancestors ate them—who knows?
It’s only the others, the graciles, that will concern us here. One at least was probably ancestral to us. Some if not all of them walked on two legs, and their (more or less) erect bipedal stance set in motion physiological changes that would come in handy when language began. Other than that, they didn’t differ that much from their ape ancestors. Their brains were little if any bigger. They didn’t make stone tools, at least not until the last one, Australopithecus garhi, and we’ll see why in a moment. Their ACSs probably didn’t differ that much from those of apes, except they very likely added predator warning calls.
NEW DANGERS AND THEIR CONSEQUENCES
Why? Let’s look at the gracile australopithecine niche. A good deal of this is inference, but given what we know of the climate, the terrain, and their physiology, they didn’t have a wide range of options. In the mosaic woodland they inhabited, fruit would be scarcer than in the forests, so they’d have to become more omnivorous than apes. Marks of wear on their teeth suggest that, though they didn’t get to growing the huge molars of their robust cousins, they relied on roots to see them through tough times. Doubtless they took advantage of things like birds’ eggs, small lizards, even caterpillars. (This may trigger your yuck factor, but modern hunter-gatherers still regard caterpillars as delicacies—in South America, an Akawaio tribesman once offered me one, several inches long, yellowish green in color, and covered with hairy warts, and he looked quite hurt when I refused it.) Almost certainly they opportunistically hunted small mammals. What is quite certain is they didn’t go after the big ones. The big ones went after them.
Something many people don’t care to think about is that our early ancestors were prey more often than predators.
In fact, there’s a recent book—its title taking off from all that macho “man the hunter” stuff that was popular in the 1970s—called Man the Hunted. Unfortunately, it’s spoiled by the political correctness of its stance (the authors think humans are sweet peace-loving folk at heart), but much of what it has to say about the perils of Pliocene and Pleistocene is all too true.
Australopithecines were small—around four feet high, weighing a hundred pounds or less even soaking wet. In mixed woodland and savanna country they were exposed to a wide range of predators larger and more fearsome than those of today. There were half a dozen genera of big cats—genera, not species; each genera contained several species. Their very names are enough to induce fear: Vampyrictis, Machairodus, Dinofelis, Megantereon. There was a hyena, Percrocuta, as big as a small lion. There was a giant weasel, Ekorus, nearly two feet high at the shoulder; since it could chase down pigs and small horses, it’s more than likely that some of our ancestors suffered the ignominious fate of being eaten by weasels. Some of them, it’s pretty certain, were killed by birds.
One of these australopithecines was the first ever to be discovered—the Taung child, a three-year-old that died around 2.5 million years ago. The back of its skull shows the keyhole-shaped incision that’s typical of an eagle strike. Its eye sockets are chipped and scratched where the eagle tore out those delicious morsels, its eyeballs. (Hopefully it was no longer alive by then.)
Think of scenes like this, then think of all those currently popular scenarios about how our ancestors’ social lives just kept getting richer and richer until they had to develop language in order to cope. Not one of the numerous statements of this thesis that I’ve read contains a single word about the ecological context in which this “increasingly complex” social life had to be lived. Obviously these authors used the ape model—just draw a straight line directly from apes to us and imagine our forebears cruising along it, sharpening their social intelligence as they went, with never a glitch in their busy social lives.
A reality check quickly disrupts this picture. Under the heavy predation australopithecines underwent, in a terrain where food was scattered and hard to come by, far too much time would have been spent watching out for and avoiding predators and struggling to get enough to eat. They simply hadn’t either the time or the security for lollygagging around like contemporary apes, full-bellied and relaxed, schmoozing and politicking away for all they’re worth. The complex “Machiavellian strategies,” the constant trying to get the better of one another that’s so often seen as the locomotive of human intelligence and language
, would have actively interfered with their primary goals: food and survival.
What would have been the real consequences of the australopithecine niche?
An increase in reciprocity among both kin and nonkin is one likely consequence. When you are at constant risk from both land and air (not to mention rivers full of ravenous reptiles), you want to make sure your buddy is watching your back, and the best way to do that is by watching his. This is the model we need to keep in mind, rather than the constant outwitting of one another, the steady escalation of mind-reading levels (“I know that he knows that I know . . .”) that Steven Pinker and others see as somehow leading to language.
The only sense in which australopithecine social life would have been richer than ape social life lies precisely in the muting of within-group competition (and, ultimately, the birth of cooperation) that follows inevitably when you have to compete with other species more than with other members of your own species. Without the abundant free time and freedom from interference that easy food-gathering and relative absence of predation gave chimps and bonobos, social life would lose much of its complexity. Group cohesiveness would increase at the expense of competition. And this is not, please note, an argument for group selection. Every australopithecine was still doing its own business, serving and saving its own genes. But to do that required, as an absolute minimum, staying alive to do it, and only cooperation with other group members—whether in giving warnings or evading pursuit or resisting attacks—could ensure that they stayed alive.
Australopithecines, related even more closely than we to the great-ape family, surely had genes that would have made possible complex competitive social behaviors, if there’d been the time and security for such things. But people often forget that, except perhaps for the very simplest creatures, genes do not mandate behaviors. They simply make them possible. Circumstances will determine how far, if at all, those possibilities are realized.
For when genes and environment pull in opposite directions, environment wins. It has to. It makes sure that those who don’t obey its demands die, and their genes die with them. In those who survive, the genes that can support elaborate social behaviors are simply expressed differently, or suppressed.
LIKE A VERVET (BUT NOT FOR THE VERY FIRST TIME!)
In fact, the situation australopithecines found themselves in had a lot in common with the situation of vervet monkeys today.
I noted a couple of chapters back the fact, puzzling to some, that while the relatively unsmart vervets had alarm calls for several predator species—things with “functional reference” that some even took as “precursors of words”—the much smarter chimps and bonobos had none. This makes no sense at all if you subscribe to the ladder of language notion, with intelligence and language precursors going hand-in-hand up the ladder. But it makes perfect sense from a niche construction perspective. From that perspective, you make whatever you need, regardless of whether you’re a “higher” or “lower” species. Vervets needed alarm calls because they were heavily predated. Chimps and bonobos didn’t, because they weren’t.
Vervets now occupy pretty much the kind of terrain that australopithecines occupied then—a mosaic of woods and grasslands. Vervets now suffer the same kind of predation, aerial as well as terrestrial, as australopithecines suffered then. So it’s more than likely that a set of appropriate predator warnings figured in the ACSs of australopithecines.
Those who think predator calls are precursors of words may want to seize on this possibility and claim predation on human ancestors as the trigger for language. They should be cautious. Australopithecine alarms would have had exactly the status of alarm calls in the ACS of vervets. They would have been situation-bound, and their automatic linkage to stereotyped reactions—hiding in bushes, climbing trees, whatever—would have stopped anyone from using them in neutral, information-exchanging contexts. (Imagine yourself having to look for the nearest tree every time I said “saber-tooth”!)
However, alarm calls might have had one positive consequence.
When we looked at the ACSs of chimps and bonobos, we noticed the absence of any kind of call that wasn’t either social or sexual. Even though alarm calls cannot be combined, and show no trace of either symbolism or displacement, they do at least direct the receiver’s attention to some objective feature of the external world—unlike social or sexual calls, which merely express attitudes toward, or attempts to manipulate, other group members. And they are also arbitrary—there is no way the “leopard call,” in and of itself, would evoke the image of a leopard or anything a leopard was likely to do. That’s to say that though they don’t behave like words, alarm calls do have two of the properties of words.
We saw in chapter 4 that trained apes, for all their undoubted intelligence, take a long time to “get it”—to grasp the idea that a signal could have objective reference—even though, once they “get it,” learning new signals comes easily to them. That initial slowness may well be due in part to the absence from their ACSs of any signals that are even functionally referential. Even if alarm calls couldn’t themselves morph into words, they might accustom their users to the notion that a signal could express more than mere feelings, needs, and desires. Such calls, in fact, could have helped get them ready for words.
THEM BONES, THEM BONES, THEM (NOT SO) DRY BONES
Meantime the millennia went on rolling by, and things were getting grassier and grassier.
Even while short-term climate changes caused things to yo-yo up and down quite a bit, the overall drying trend went on. Forests retreated eastward and upward, toward the summits of the Central African mountains that still caught moist air from Atlantic winds. Woodlands split and shrank, reduced to narrow galleries along shriveling watercourses, or vanished altogether. The grasses took over, rippling in the wind, lion-colored once the brief rains had passed. In this strange new landscape, our ancestors had to survive.
In all probability, they almost didn’t.
For omnivores, savannas make living tough. Fruits and nuts become rare. The robust australopithecines, with their massive tuber-chompers, could still make a living of sorts. Apart from them, and apart from mammals and reptiles small enough to live on insects, all savanna dwellers must be either herbivores or carnivores.
Other primates that had adapted to savannas, baboons for example, had gone the herbivore route. But baboons had had millions of years in which to develop an appropriate digestive system. The gracile australopithecines didn’t have the luxury of indefinite time. They needed a solution right there and then, or they’d go under.
Carnivory seemed like the only way to go. Since all great apes consume meat from time to time, this did not present a digestive problem. It did present logistical problems. In forests, for instance, chimps are able to kill monkeys by surrounding a tree with a monkey in it and cutting off all its escape routes. How do you do that in open grassland, where every degree in the 360 is a potential escape route? Superior speed, at least over short distances, is the answer for many australopithecine-sized predators. But whatever the advantages of bipedalism, four legs are usually faster than two.
Of course, there’s always ambush hunting. A primate intelligence should have been good enough for that. And I’m sure australopithecines hung out around waterholes, hidden by long grass, motionless for hours if need be, waiting for the chance to pounce on a surprised animal before it had time to react. But when you’ve got that far, what do you do? If your prey’s about rabbit size, you can wring its neck. Anything much bigger, you have problems. You don’t have any of the right carnivore equipment—strong jaws with sharp teeth to seize necks, hooked claws to rip out intestines. Try to kill even a small deer bare-handed, you’ll see what I mean. And as far as we know, at this stage in our ancestors’ development they had no weapons whatsoever.
In fact I’d like to take anyone who still believes our remote ancestors lived by hunting, drop them in a modern savanna foodless and empty-handed, and see how long they surv
ive. Well, not entirely empty-handed—I’m soft-hearted enough to leave them a cell phone so I could come get them when they cry uncle. It would make great TV, if nothing else.
Joking apart, there’s just one kind of hunting they might have developed, and that’s endurance hunting.
We know that endurance hunting is still practiced by some of the few contemporary hunter-gatherers that are left. We don’t know how far back it goes. An endurance hunter simply picks out an animal and runs after it. Of course, over a short distance the animal can run much faster. But it can’t run indefinitely, and the hunter can.
That’s one of the big payoffs of bipedalism—you may not be fast, but you’re steady. It’s unlikely that endurance hunting was what originally selected for bipedalism—it must have taken hundreds of thousands if not millions of years to achieve the physical infrastructure, the stamina, and the muscular control to make endurance hunting successful. But once these things were in place, endurance hunting presented prey animals with a situation they may never have faced before. Most other predators burn out after their initial dash. If that dash isn’t successful, they break off, relax, build energy for their next shot. Prey animals had no strategy to cope with a predator who, like an Energizer battery, just kept on going. Sooner or later they would collapse, semiconscious. Even if you had nothing to kill them with, you could just wait while they died of thirst and/or exhaustion.
The problem with endurance hunting is that while doing it you may end up as prey yourself. It’s not something a large group can do, because with a single animal—and one small enough to run instead of just charging you—there won’t be enough meat there to make it worth the group’s while. So you alone, or at best you and a buddy or two, will be out there away from the protection of the group, maybe many miles away, maybe for days at a time, with no good means of defending yourself. Since you’ll be in almost constant motion, you will quickly register on the gaze of any other predator, whose eyes will be constantly sweeping the savanna for its next dinner.
Adam's Tongue: How Humans Made Language, How Language Made Humans Page 14