From zoo observations of chimpanzees with offsprings
The below glimpses, narrated in anthropomorphic terms, are from the daily life of group of half-wild chimpanzees which I have studied through video-recordings, observations and drawings in the Kristiansand Zoo and Wildlife Park in Southern Norway. The group comprises two adult males (the Alpha male Champis and the Beta male Kjell), three females (Josefine, Biny, and Dixie) with offsprings, including the male youngster Jesper.
Imitation of odd walking and "baby-sitting" posture
The five year old youngster Jesper is often at play with either of the two grown up males, with Champis who is the largest, and with Kjell who is smaller and slightly deformed, and walks in a peculiar manner. In play sequences with each of two male adults which appear very spontaneous, Jesper appears to be deliberately imitating what the adult is doing. Most striking was the way in which Jesper once followed Kjell around, walking behind him in the same peculiar manner of asymmetric limping ground movements as exhibited by the adult Beta male.
This Beta male, Kjell, is used by one of the mothers, Biny, to watch her infant (one year) while the mother goes in search for food or drink. When she gives a sign to Kjell he immediately comes and assumes, as she goes away, a position and bodily posture that is almost identical to the way in which Biny had been sitting, watching her offspring.
Anticipating the movements of a "property holder"
When one of the mothers (Josefine) was once occupying the platform (on the inner island) which usually another mother (Biny) occupies, Josefine observes that Biny from afar begins to move in the direction of her platform. Even though Biny is 10 metres away, Josefine at once leaves the platform. But then, when Biny changes her direction and goes elsewhere, Josefine resumes her position on "Biny's platform".
A mother's "medical care" prevents suffocation and releases holding behaviour
When Josefine's infant was 25 days old something critical happened.. The infant tried to cough and tried to cry, but was unable to cry or cough. Josefine went into action. First she put her small finger inside the tiny mouth of the infant. Then she opened her mouth widely, and had the baby's head inside as if to swallow it. She formed her lips like a track and began sucking. After a while she opened her mouth and extended her tongue to the on-looking attendants. On her tongue was a 6 cm. straw with a catch at the end. First, by using her finger and her mouth, perhaps also her tongue she saved the life of her offspring.
Since this event, and when returning to the flock, Josefine's holding and caring behaviour changed. Before this event Josefine had been showing signs of not getting accustomed to the motherhood situation. She had lost her first newborn in the water two years earlier, giving birth sitting at a tree branch. Having her second birth, Josefine at first appeared very uncomfortable with her offspring. She would not allow the infant to cling to her body, holding him away from her body, sometimes even upside-down. Now, after this event of near-suffocation, she allows her infant to cling to her, and constantly grooms the infant, cleaning his eyes with her tongue, and so forth. She has also become very protective of her infant, and pushes away young Jesper (Dixie's offspring) whenever he gets too close in his efforts to hold her infant.
Two different "situational definitions" of a similar event
One day Jesper (5 years) kept pestering Josefine, clearly wanting to hold her infant. When she turns away from him, he gets angry and throws things at her. Finally -- after one hour of having been pursued and pestered by Jesper, she "lost her patience" and bit him. At Jesper's shrieking, the whole flock reacted instantly, came running towards them and shrieking at Josefine. Biny, the other mother, usually so close with Josefine, slapped her. Even Kjell, the "baby sitter", pushed her. The next week, the same development occurred. Again, at Jesper's shrieking, all the others came running. But this time, they turned against Jesper and took him away from Josefine and her offspring.
Anticipating punishment because of "disobedience"
When the weather is not too cold and it is nor raining, the chimpanzees shift between being inside and out in the open on a small island. a small bridge connects the inside to the outside. The Alpha male, Champis, is always to first to cross the bridge, and the others follow him. On the island they scatter around, not always grouped together. But when returning inside, Champis will again be in the lead and first cross the bridge to the inside, with the others following. One rather chilly day, two of the others, Josefine with her offspring, and Kjell, the Beta male, had been by themselves on the island, and did not manage to catch up with the others when they crossed the bridge to the inside. The big male then sat down inside the door, close by the opening as if watching out for them. Cautiously Josefine and Kjell approached the bridge. But when noticing the watcher inside the door, they withdrew. They remained sitting down outside in the grass, in the cold, as it were, not venturing another entrance at this stage (Figure A1.1). From time to time one of them would made another advance towards the bridge, even halfway entering it, before again withdrawing when noticing that the big male was still sitter there inside the door.
Performance with "pretense"
An electrically elevated trapdoor opens for the chimpanzees to cross a bridge to the outside. The door is opened when the attendant in an observation room on the opposite side of the inside island pushes a button. In the morning, after they have been given food, the big male is sometimes impatient for the door to open so that they may get out in the open. One morning he demonstrated his impatience by running around in apparent anger, halfway slapping and feigning slapping the others and eliciting shrieks around. After such a round, he would pause and look towards the attendant's room. The trapdoor remained locked. The big male resumes his running around and made slapping movements towards those which he passed, which again evoked shrieking. Again he looks toward the room on the other side. Still, no reaction. Only after the chimpanzees had calmed themselves, was the button pushed that opened the door. The next morning, the big male repeated his performance. Again, no reaction. In the mornings to follow there were no more performances of this kind.
Moving with the mother's movements
When riding on the mother's back the infant appears to be moving with her movements as she moves about. In this position infants frequently adjust their head to her head direction, appearing to be following her gaze. Such joint movements are less apparent when clinging to the back of a sibling, for example, when Dixie's offspring (6 years) is allowed to carry his sister (5 1/2 month).
1 I thank the staff and the director, Edward Moseid, of Kristiansand Zoo and Wildlife Park, for all their support and help in facilitating these observations. Most of the episodes recounted in this appendix were mentioned in my dinner talk 29 August 1994 in The Norwegian Academy of Science in connection with the first Theory Forum Symposium.