Intertroop relations of chacma baboon (Papio ursinus)

Intertroop relations among four troops of the chacma baboon population on the Suikerbosrand Nature Reserve, southern Transvaal, South Africa, were studied for 18 months using radiotelemetry. Encounters between troops occurred only rarely and were relatively nonantagonistic in character. Dominance among the four troops was difficult to identify by means of behavior although differences in range quality among the four were marked. The way in which intertroop relations affected the fitness of members of each of the troops was, therefore, unclear. Transfer of individuals from one troop to another was easily accomplished by both males and females and probably negated the effects of differential range quality on individual reproductive fitness.     

The brachial plexus in the chacma baboon (Papio ursinus)

Abstract: The brachial plexus in each of ten embalmed, mature chacma baboons was dissected to document the structure and branching pattern of this nerve plexus in this increasingly used research animal. In general, the brachial plexus in the chacma baboon was similar to the plexuses in the vervet and other Old World monkeys. However, several aspects were comparable to those observed in domestic animals. Thus the bipedal and quadrupedal abilities of the chacma baboon were reflected in the structure of its brachial plexus.     

Distribution and population estimate for the chacma baboon (Papio ursinus) in KwaZulu-Natal, South Africa

We report the current species distribution and population estimate for the chacma baboon (Papio ursinus) in KwaZulu-Natal Province (KZN), South Africa, based on an analysis of estimated area of occupancy and estimated home range size. This estimate suggests a total population size of approximately 11,000 individuals for KZN. Much of the province is uninhabited, with a density in occupied areas of approximately 1.8 animals per km(2). The current population size may be more than an order of magnitude smaller than historical population size. Chacma baboons now exhibit a highly fragmented and discontinuous distribution in KZN, with 58% of the population residing within protected areas, and more than half of these troops reside in areas >1,500?m above average sea level. The small population and highly fragmented distribution of chacma baboons in KZN, combined with rapidly increasing human population size and transformation of natural habitat, suggest this species requires greater conservation attention.     

Inbreeding and reproductive success in a natural chacma baboon,Papio cynocephalus ursinus,population

Six of 19 male chacma baboons living in a natural environment in Botswana were born in troops where they attained alpha status. At least three of these six males sired young in their natal troops. Nine other paternal males were immigrants, hence they were more distantly related to their mates, who were all natal. Offspring of natal and immigrant parents survived equally well to 90 days. These observations suggest that for this and other mammalian species the evolutionary history of a population may determine inbreeding costs.     

Molar enamel thickness in the chacma baboon, Papio ursinus (Kerr 1792)

Modern humans exhibit increasing relative enamel thickness from M1 to M3. Some biomechanical (basic lever) models predict that the more distal molars in humans encounter higher occlusal forces, and it has been postulated that this provides a functional explanation for the observed gradient in relative enamel thickness. However, constrained three-dimensional models and experimental observations suggest that there is a reduction in bite force potential from M1 to M3, which would be consistent with the tendency for humans to reduce the size of the distal molars. In this regard, it has been postulated that the distal increase in enamel thickness is a consequence of crown size reduction; thus, it is unnecessary to invoke functional scenarios to explain this phenomenon. We assess these competing proposals by examining relative enamel thickness in a catarrhine primate (Papio ursinus) that exhibits crown size increase from M1 to M3. The molar row of P. ursinus is positioned relatively far forward of the temporomandibular joint, which results in the baboon being able to exert relatively greater muscle forces during posterior biting in comparison to modern humans. Thus, a significant distalward gradient of increasing enamel thickness would be expected in P. ursinus according to the hypothesis that posits it to be functionally related to bite force. The present study reveals no significant difference in relative enamel thickness along the molar row in P. ursinus. This finding lends support to the notion that the relatively thicker enamel of human distal molars is related primarily to their reduction in size. This carries potential implications for the interpretation of enamel thickness in phylogenetic reconstructions: the relatively thick molar enamel shared by modern humans and some of our fossil relatives may not be strictly homologous, in that it may result from different underlying developmental mechanisms.     

Atrio-ventricular block in a baboon (Papio ursinus)

Atrio-ventricular (A-V) block occurring in an anesthetized chacma baboon (Papio ursinus) is analysed. Hemodynamic, 12-lead electrocardiographical (ECG), hematological and biochemical parameters were monitored and data before and after block are compared. Though biochemical and other abnormal values were encountered, no conclusive evidence of the cause of the block was found.     

Rank and density correlates of inclusive fitness measures in a natural chacma baboon (Papio ursinus) troop

Some demographic characteristics of a group of chacma baboons (Papio ursinus)in a natural environment in northern Botswana were monitored for an 8-year interval. The group size ranged from 73 to 43 individuals. After 3 years at a high density, the group size declined over a 2-year interval, then stabilized again at reduced numbers (−41 %) and biomass (−40%) for over 2 years. The reduction in group size and biomass was followed by an increase in fecundity, greater for high-ranking than for low-ranking females. At the larger group size, survival was lower for infants born to low-ranking than to high-ranking females. Infant survival rates by female rank were equal at the lower density. The mean weight of adult females increased as the density decreased, but there was no correlation between female rank and body mass. We conclude that there is a negative relationship of density to individual condition and reproductive success and that there are fitness advantages to high female rank.     

The social interactions of adult conspecifics with an adult XY gonadal dysgenetic chacma baboon (Papio ursinus)

Two separate behavioral studies on an XY gonadal dysgenetic chacma baboon were carried out. In the first experiment the focal subject was treated identically as the control females by her adult male test partners. In contrast to the controls in this experiment the dysgenetic animal reciprocated the agonistic behaviors directed by the males toward her. In the second study intact and castrated males as well as ovariectomized females served as controls for the dysgenetic subject in tests with ovariectomized adult females. The stimulus females presented more to both classes of males than either the subject females or the gonadal dysgenetic individual, suggesting that the focal subject was treated by other female conspecifics as a female.     

The influence of physical and chemical restraint on the physiology of the chacma baboon (Papio ursinus)

The chacma baboon (Papio ursinus) is extensively used in South Africa for biomedical research. Being a large primate, it is always necessary to apply some measure of chemical or physical restraint. The physiological effects of placing an animal in a restraint chair are compared with the effects of various chemical agents, such as ketamine, halothane, and ketamine/xylazine combination over 90 min. It was found that ketamine and thiopentone infusion were a satisfactory chemical restraint agent that gave a stable physiological state over 90 min.     

Observations on spontaneous pathological lesions in chacma baboons (Papio ursinus)

Some pathological findings made in more than 3000 autopsies on Chacma baboons (Papio ursinus) are reviewed. Diarrhea is frequent among newcomers in the Primate Colony at the University of Stellenbosch and is possibly related to the stress of adaptation to captivity. Strict control of the water balance of sick animals prevents losses. In 63% of diarrheic baboons cortical adrenal necroses were found. About 10% of the autopsied baboons had a cardiomyopathy. In 50% of the baboons with necrotizing cardiomyopathy adrenal cortical necroses were found. In contrast to man, the Chacma baboon deposits inhaled inert dust in small granulomata similar to early cellular lesions of silicosis. Pyelonephritis unrelated to experimental procedures was found in 0.3%. Six cases of chronic glomerulonephritis were encountered. The inclusion of the lower parathyroids in the thyroid must be considered as a normal finding in Chacma baboons; thymic inclusions in the thyroid are more common than in man. On the whole, there are only minor differences in pathological reactions between Chacma baboon and man, but the former is much less resistant to stress than the latter.     

Habitual cave use and thermoregulation in chacma baboons (Papio hamadryas ursinus)

The willingness to utilise caves as shelters is held to have been important to early humans but dependent on pyrotechnology. Despite anecdotal evidence that non-human primates will also exploit caves there has as yet been no detailed account of such exploitation or of the reasons underlying it. Here we provide the first such data, on the frequency and patterning of the use of an underground cave system by baboons (Papio hamadryas)—and show that usage is determined, at least in part, by above-ground temperatures.     

An experimental examination of the colour component in visually mediated sexual arousal of the male chacma baboon (Papio ursinus)

Male chacma baboon ( Papio ursinus ) sexual arousal response as gauged by the coagulated seminal emissions resultant from masturbatory activity was experimentally assessed. Males were initially exposed to an ovariectomized female prior to and during daily oestradiol benzoate treatment. Males were then re-exposed to the same female prior to and during the wearing of a thermoplastic model of a swollen female perineum. A total of eight different colours were sequentially applied to the model. It was only the red model that elicited a response similar to that shown to the oestradiol-treated female. The behavioural data collected from the stimulus female supported the view that it was model colour that determined the differential male response.     

The effects of captivity stress on the blood chemical values of the chacma baboon (Papio ursinus).

Baboons were trapped and transported to the colony within 3 days of being captured. Blood was collected on Tuesdays and Fridays for blood chemical determinations. The changes in albumin and globulin resulted in marked changes in the albumin: globulin ratio. Cholesterol values showed a sudden and marked drop and the values were still below normal at the end of 9 weeks. Blood sugar values increased to significantly elevated levels and marked changes occurred in the enzyme activity and plasma corticosteroid activity. Male and female animals differed in their response with regard to the values found in some parameters. A period of adaptation or conditioning of 8 weeks was found to be required for an animal to reach stability in its blood chemical values.     

Quality of semen obtained by electroejaculation from chacma baboons (Papio ursinus)

Fifty-four baboons (Papio ursinus) were subjected to an electro-ejaculation procedure that yielded 683 usable ejaculates in 705 attempts. Quality evaluations by usual human spermiogram methods were applicable with only minor modifications to the procedures. By human criteria these wild baboons remained fertile after capture, and their use as a fertility model in pharmacological studies appeared to be appropriate.     

Behavioural and hormonal responses to predation in female chacma baboons (Papio hamadryas ursinus)

In humans, bereavement is associated with an increase in glucocorticoid (GC) levels, though this increase can be mitigated by social support. We examined faecal GC levels and grooming behaviour of free-ranging female baboons to determine whether similar effects were also evident in a non-human species. Females who lost a close relative experienced a significant increase in GC levels in the weeks following their relative's death compared with the weeks before, whereas control females showed no such increase. Despite the fact that females concentrate much of their grooming on close kin, females who lost a close female relative did not experience a decrease in grooming rate and number of grooming partners; instead, both grooming rate and number of grooming partners increased after a relative's death. While the death of a close relative was clearly stressful over the short term, females appeared to compensate for this loss by broadening and strengthening their grooming networks. Perhaps as a result, females' GC levels soon returned to baseline. Even in the presence of familiar troop-mates and other relatives, females experienced a stress response when they lost specific companions, and they apparently sought to alleviate it by broadening and strengthening their social relationships.