Among modern hunters and gatherers, men and women usually go separate ways, the men to hunt, the women to gether. Although women sometimes hunt and men sometimes gather, the basic division remains. Then the men and women meet to share what they've collected or killed. This division of labor gave hominids a distinct advantage. Because women are usually pregnant or carrying infants, they are not very efficient hunters, especially of large game. But motherhood does not interfere with gathering fruits, nuts, and roots. Free from pregnancy and nursing, men are better hunters. But hunting or even scavenging is always a gamble, especially for a relatively puny hominid competing with 'hunting machines' like the great cats. Hunting does not provide a steady, reliable source of food. However, combining hunting and gathering was a revolutionary development, one that enabled the early hominids to take full advantage of their mobility and invade new habitats.

There is a catch, however. If men go one way and women another, yet they depend on one another, they need some reliable way to arrange rendezvous. This is where speech comes in. Speech might have volved because it made it easier for our distant ancestors to coordinate their activities. Once speec evolved, it probably developed its own momentum. Not only could men and women coordinate today's activities, they could communicate their individual experiences and use the past to plan for the future, and over time develop a collective information bank, or what we call 'culture'.

Almost certainly, speech was one dividing line between our hominid ancestors and the great apes. But one must distinguish between speech and language. The great difference between pongids and humans is spoken language. The great apes are incable of speech; they lack the vocal apparatus that speech requires. But great apes can be taught a simple language, as the chimpanzee Washoe, the gorilla 'Koko', and the lesser known orangutan Princess will attest. Great apes can learn that gestures or other symbols stand for individuals, objects, actions, emotions, even categories, and that the order of symbols can change the meaning (syntax). They not only learn to recognize and produce symbols, but combine them in novel ways. The great puzzle is why, if the great apes have latent linguistic abilities, they never developed this asset.

Again, orangutans gave me an answer. When Gary Shapiro left camp in the early 80s, his prize pupil, Princess, has learned more than thirty signs. But as I watched Gary ride a graduate student's roller-coaster of highs and lows - highs because Princess and his other orangutan subjects could sign with the best of them, and lows because the orangutans mainly wanted to sign about food and contact - I realised why orangutans don't have spoken language. They don't need phonemes, words, and sentences. Quite simply, they have nothing to say to one another that can't easily be communicated through facial expressions, gestures, movements, and vocalisations. Why build a rocket ship when you only want to move from one tree to another?

A fourth distinction between pongids and ourselves is our birth interval. Perhaps my most important single discovery is that orangutans are one of the slowest breeding mammals on the planet. Certainly, orangutans are the slowest breeding primate. At Tanjung Puting, orangutan females give birth, on average, only once in eight years. So far, the greatest number of offspring I have seen a wild female orangutan produce is four. But the average adult female bears three offspring or fewer in her lifetime. Maud, with three offspring by age thirty, is already leading in the evolutionary sweepstakes.

At the same time, wild orangutan mortality rates are low. In all my years at Tanjung Puting, only one orangutan unit - Carl, Cara, and Cindy - died from disease, probably facilitated by nutritional stress. Other orangutans died of old age. But infant mortality and predation are virtually nil. This contrasts with a troop of wild crab-eating macaques who occasionally appear at the end of the camp bridge. During casual observation of these small gray monkeys we saw on three separate occasions, individual macaques fatally attacked by predators including a corcodile and a large python. But these monkeys can 'afford' their high mortality rate because female macaques give birth every two years.

An orangutan female is doing well if she bears three or four offspring in her lifetime. A chimpanzee female may produce one offspring every six years, and a gorilla female, one every four. But in many traditional societies, women have six, eight, or ten children (not counting infant deaths). Monkeys are always fast reproducers, bearing offspring every year or two. But humans outmonkey the monkeys in fertility. In terms of reproductive strategies, great apes, especially orangutans, took the slow but safe route. Monkeys took the fast but rising route. Humans took the fast route but made it safe through the division of labor and, later, food production and technology. Perhaps this is why humans colonized the planet, leaving their pongid cousins behind. Certainly, this is why orangutans are so vulnerable to extinction, while humans are overpopulating the planet.

The ancestors of today's orangutans, who remained in the tropical rain forest, retreating with the forests to Asia ten million to fourteen million years ago escaped this fate. When I look at orangutans I am reminded that we are human. Our appearance on the earth was relatively recent; orangutans are older, as a species, than we are. I wonder, when Homo erectus strode into Asia, were orangutans watching from the trees? It's a humbling thought.

Our departure from Eden allows us reflection - reflection on our origin and our relations to other creatures, reflection on good and evil, and ultimately, reflection on the possibility that we are engineering our own extinction. Never having left Eden, our innocent pongid kin are not burdened with this knowledge and the responsibility it entails. Looking into the calm, unblinking eyes of an orangutan we see, as through a series of mirrors, not only the image of our own creation but also a reflection of our own souls and an Eden that once was ours. And on occasion, fleetingly, just for a nanosecond, but with an intensity that is shocking in its profoundness, we recognize that there is no separation between ourselves and nature. We are allowed to see the eyes of God.

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