A Study of the Behaviour of the Chacma Baboon, Papio Ursinus

i. In this paper an attempt has been made to describe the behaviour of the Chacma, and to make an analysis thereof. The observations were made on two young captive baboons, Joe and Jenny, as well as on wild ones. ii. There is a hierarchical organisation of the troop which mainly shows itself in feeding and mating. Among the females the hierarchical order is less obvious than among the males. It seems as if females in oestrus are of higher rank than those in anoestrus. The male-female association is often very casual and the formation of permanent family groups are rather the exception than the rule. Idle males act as sentinels. iii. A. All sounds emitted express emotion. Various sounds and their emotional motivations are described. B. In the typical threat posture the animal stands facing the opponent with lifted head, stiff arms and hairs on shoulder and back raised. It looks straight at the opponent. Often it snarls and its movements are rigid and jerking. It may rub the ground with its hand or stamp with it. It then suddenly darts forward in attack. C. The opponent is pursued and, if caught up with, is bitten, usually in backhead and shoulder, or, if smaller rubbed against the ground. Other baboons come to the rescue of the defeated individual. In nature this leads to a wild chase. In captivity it may end up in some mass fighting. D. Baboons have great respect for authority. E. In the retreating submissive behaviour the animal crouches and moves with its side or tail towards the aggressor. The teeth may be bared in horror and the aggressor is watched evasively over the shoulder while the retreating animal presents its hindquarters. F. Yawning and scratching are commonly noticed in sentinels. They are considered as displacement activities, signifying nervous tension. G. When eating the baboons frequently rub their food against their fore-arm. It may signify nervous tension. H. Sexual behaviour has given rise to many other activities. a. Great interest is often shown in females in oestrus, the genitalia of whom are often examined by other females and juveniles. b. Mating is initiated by lipsmacking and presenting from the female. c. Masturbation and onanism is common in inferior males without a female. d. Inverse and homosexual behaviour is common in captivity. e. Presenting is a friendly and inviting gesture with a sexual origin. f. Lipsmacking is a very much used friendly and inviting gesture, probably with a sexual origin. I. Grooming is a typical female activity. It is impossible to explain its significance. The concentration with which the act is performed seems to indicate some physiological background. J. The various types of behaviour have been analysed and their elements and significance listed. K. In cases of opposing emotional motivations the elements of behaviour are combined in characteristic ways which are interpreted by the onlooking baboons. L. Female baboons are usually fond of very young individuals. The mothers usually look very well after their babies during their first few weeks, but the interest gradually fades after the young ones have been weaned and begin to stray about. They show great interest in each others' babies. The maternal instinct is developed already at an age of six months or less. The attitude of the male towards the young varies from complete intolerance to great affection. Two cases of males acting as mother substitute are described. M. The young individual always knows its guardian and seeks its protection in case of danger. N. In play, the young haboon includes almost all the activities of the adult. Fighting, biting and mating are some of the main features. The various types of bites are described. The play copulation includes the full ritual exhitited by adults during their mating. It is surprising to find that the innate ritual is fully developed in youngsters only a few months of age. O. Any object can be of value to a baboon. Its value depends on the interest shown in it by other individuals. P. Baboons are primarily vegetarians, but they love in addition to their diet of insects and probably birds' eggs. Occasionally they turn carnivorous. Q. Much food is dug up from the ground or collected under stones. The turning of stones is an innate behaviour which is performed at a very young age. R. Baboons seem to have an innate fear of snakes or other cylindrical bodies which can bend and wriggle. Towards other animals which do not serve as food they normally show indifference. On occasions however, the juveniles take pleasure in teasing other animals. Cases where kudu and lions were teased are described. In the latter case the mature males attempted to maintain order among the juveniles trying to prevent them from approaching too close. This action seems to indicate that the rescue responses can not be explained as a simple reflectory response.