I have always had a close connection to the natural world, the plants, the animals, and characteristics which they possess. I have always loved animals. I know when my dog is sad; I know when she has done something bad by the look on her face and the way she walks. I know when my cat senses something wrong, I can tell when she is waiting for me to go to bed so she can too, and what her smile looks like. I know that my animals exhibit human characteristics in the way they act. But there are other animals that are so human-like that humans sometimes refer to them as people. These are the great apes. In this family are the common chimps, bonobo chimps, gorillas, orangutans, and humans.
It takes an expert to differentiate between a baby ape skeleton and a baby human skeleton. In fact, we share 98.8% of our genetic makeup with chimpanzees. I could get a blood transfusion from a chimp; I could have their bones safely grafted to my skeleton. They are very much like what our ancestors must have been like; utilizing tools, language, having complex social structure and behavior.
"If you want to see a stand-in for what human ancestors looked like, and acted like, five million years ago, go and watch a band of bonobos in a zoo." (Calvin, William H., 2001, http://williamcalvin.com/teaching/bonobo.htm) Calvin is referring to the Bonobo Chimpanzees. Surprisingly enough, they walk upright from time to time, to carry food around. They make and use primitive tools, have complex social order, and even have abstract language. In the trails through the forest, the bonobos leave leaves arranged in a pattern to indicate which direction on the path to follow. This shows a characteristic that all chimpanzees posses: the ability to anticipate, and to comprehend cause and effect. One chimp must think "someone else is going to come this way and wonder which way to go, so I will leave him a sign." To anticipate a future event, one chimp’s following his own trail, and to understand that that chimp will not know which way to go shows high intelligence.
I watched a documentary centered around primates (Walton, Bernard, 2000, BBC/Discovery Channel). A young male was with his mother and her two infantile twins. He wanted to join up with the other males from his group that were some distance away, but he wanted his mom to go with him. Somehow, he had to get her to follow him. He carried one of her babies over to the group, and his mom followed with the other twin. He had thought of a plan, one that would require him to anticipate what a separate individual's action would be correlating to his own. This psychological guessing game requires immense brainpower, reasoning, and abstract thought. The documentary went on to show a group of chimpanzees that had mastered several forms of tool making.
These chimps manipulate a rock until the desired flat and level side of it is facing upwards. They then place the hard-shelled nut they wish to crack on their primitive anvil. Using a third object (another rock) they hit the nut in just the right spot, so as to not crush the nutmeat, but to crack open the shell. Several researchers attempted this, but on each attempt, were left wanting an ape tutor. This hand eye coordination is demonstrated in humans- typing, drawing, playing the piano, playing Super Mario Kart… This leads to the fact that both humans and chimps are either right-handed or left-handed. This in turn leads to the fact that one must have specialized brain halves, the fact that allows us to have language, imagination, and creativity. Chimps also have the ability to make a tool for fishing termites and ants out of their hard nests. When one chimp went out to eat biting ants, she stood far enough away so that they could not climb up her and bite her. She half stood, half hung on a tree, and leaned forward to poke her fishing device into the hole.
"Bonobos and chimps are our closest cousins among the apes. The uncommon social structure, sexual behavior and intellectual capacity of bonobos give us a unique glimpse of the roots of human nature." (Calvin, William H., 2001, http://williamcalvin.com/teaching/bonobo.htm) This brings up the interesting characteristic of sex in bonobo society. Unlike most other ape societies, bonobos are centered around a female dominated group. They use sex as a way to resolve conflicts, and for pleasure, not for the sole purpose of furthering the species, as most other living things. This takes away a great deal of the social stresses experienced by other primates.
Baboons suffer from social stress in a way that most people can. In fact, they suffer from peptic ulcers, hardened arteries, and heart disease (the same ailments humans suffer from related to stress). Why? The top male baboon of the troop dominates the younger and weaker males, causing them to suffer psychological distress. Very rarely are there fights, but "the thought of what could happen" (Sapolsky, Dr. Robert, 2000, Inside the Animal Mind), and the stress of having the dominant male breathing down their necks creating a deliberate air of tension, is enough to make any baboon walk on eggshells. A stressed baboon's body produces the same hormones and chemicals as those produced by a depressed human
People can be traumatized, and their behavior can reflect that. Chimps can suffer from past memories as well. After a psychologically distressing event (no one knows for sure, but could it have been from seeing her mother shot and being hacked to pieces and then having herself shoved into a bag with her mother's hands and feet and head?) she would not come out of her cage her whole life. Another chimp sits in his cage hitting himself. That's all he does, is sit there and stares despondently at nothing, hitting himself. They have memories, and they can be disturbed and frightened by those memories, even though there is no immediate threat. Usually fear is an evolutionary adaptation for immediate survival; there's a wolf; run away, there's a loud noise; run away. But you cannot run away from a memory, and the complex brain of apes allow them to remember, to feel emotions relating to that memory, and to even withdraw from their lives as a direct result of that memory.
The amount of social order is directly related to how developed and complex an animal's behavior is. An advanced brain allows for more complex emotions, such as guilt, shame, and love. Love… How can you scientifically study that? Who knows. But in watching a certain documentary (Walton, Bernard, 2000, BBC/Discovery Channel), I learned that the indri lemurs live in what we used to consider a nuclear family. A husband, a wife, and their children make up their little group. The husband and wife share a monogamous bond. They sing to each other to reinforce it. They perform these articulate duets, starting off simply, then heightening their song to a loud vocalization of each other's… love? Why are they monogamous? Do they experience love in the way that humans know it? Love can be measured by the brains output of hormones and chemicals; try putting an electrode on a lemur long enough for it to sing to it's mate… They do show each other affection, as with other apes.
Chimps will hug one another. They even kiss as a greeting. They hold hands, they walk with an arm around their friend's shoulder, and they have a bond with their mother for the rest of their life. Those are certainly things that humans do. It would appear to be affection. Sadness can be measured. I have read of a mother chimp dying of sadness after her baby died. Chimps that lose their mother when they are still adolescent withdraw from the group, become depressed, and remain in a state of mourning for weeks. Chimp body language can be read similar to that of our own, although our facial expressions differ slightly (a smile is not happy). A chimp sitting hunched over and making the characteristic anxious whimper is sad. But if you look at their face, their eyes do share the expressions we have come to know as human. You can tell from their eyes.
Judging from their behavior, we can tell that apes can be happy. Sure, endorphins are probably coursing through their blood to their brain, but who wants to try and get a gorilla to wear all those monitoring devices? Who needs it anyway? All you have to do is watch them! They play! They run, jump, swing from trees, chase each other, wrestle, and roll around on the ground… Not to ward off a predator, not to establish that that area is exclusively their territory, but to have fun! Sifakas have designated "playgrounds" where there is no vegetation to get in the way of play, where they can chase each other and not be grabbed at by ferns and such. And all for the express purpose of having fun.
Other human emotions are present in apes. This also brings out the fact that apes are not the cute and friendly version of the human race; they too have a dark side. The act of infanticide is not considered a human trait, nor is it a regularity in ape society (only when a new male overthrows the old leader he will kill any infants so that he may procreate his own genes), but this infanticide shows that jealousy may have been a factor. "The actual act in this instance was rather gruesome, and the mother suffered a considerable mauling in her efforts to protect her offspring by using her body as a shield." (Preston-Mafham, Rod and Ken, 1992, p.98-118) First off, that phrase demonstrates a mother chimp's devotion to her child. But the background behind the actual event reveals that there was abstract thought at work in this killing. The male members of the group suspected the mother of siring the baby with a male from a neighboring group, as she had been absent from them for a time. Researchers knew that in fact, the baby was one of their own, yet they killed it anyway, because they were jealous, and they wanted retaliation for her leaving the group, if only for a short while.
One day, nine chimpanzees left their group to create a new one. After they left, males from their original group were sent out on mercenary execution missions. Five or six males would seek out a lone member of the new group. They would then brutally attack it and leave it to die. This went on for six years until the new group was entirely wiped out. That was a planned event. So to are the chimpanzee hunts.
They stalk their prey (usually a monkey) from as much as a third of a mile away. They send members of the party ahead, and others chase forward the prey, then they all maneuver it into an isolated clump of trees. From there; no escape. Communication between hunters designates what position each is to take. The hunt can take as long as two hours, and when a kill is made, they hoot and holler and dance around the carcass and gather round it to eat.
The possession of language is not solely a human characteristic. Apes do have complex body language, but their physiology does not allow them to have complex verbal communications in the sense that we do. Chimps have over thirty distinct sounds. But for all apes, their physical limitations do not mean they cannot learn language. Several gorillas and many chimps have been taught ASL and can communicate their thoughts and emotions in terms that humans can understand. They can even teach others of their kind whatever knowledge they have, be it ASL or how to get ants out of a hole.
Apes have an awareness of the world around them. Gorillas actually mix the leaves of a bitter but nutritious leaf with that of bamboo to make it taste better. Research is only now beginning to reveal that chimps and gorillas may use plants for their medicinal properties. Many years ago, mountain macaques observed people bathing in the hot springs of the snowy valley in their territory. They soon joined in, and the rest of their troop followed. It was too much; the people wanted it to themselves. So they built the monkeys their own hot springs farther up the valley, where the macaques share it, and still go there to laze around in the steaming water as snow flakes on their fur.
Primates share so many things with humans, that no one thing is distinctly human anymore. It is only the way in which we use our skills that differ… Using a rock to crack a nut versus making a car to get where you want to go. Thirty odd vocalizations occur naturally, but the chimps can learn more communication skills if we teach them. Even our emotions, much harder to understand, are not all that different. That old saying, a picture's worth a thousand words, I would have had two pictures make up this essay: one would have been of a chimp group centered around a mother as she cradled her dead infant. It would show clearly the facial expressions of the group, and you could see sadness and sympathy written in their eyes like the words of this essay. They other would have been of a bonobo chimp standing up straight, dragging a branch behind it. This picture is embedded in my mind as what our ancestors might have looked like 5 million years ago. Or perhaps a picture of one chimp teaching another how to use ASL… The fact that he knows ASL and how to use it, and that he has the capacity to teach, and that another of his kind has the capacity to learn from him. All human characteristics, and ones which blur the line between a conscious being and an unconscious one.
We are not alone in our emotions and abilities. Primates share many human characteristics, and now it seems we can talk to them about it.