Estradiol benzoate treatment of an XY gonadal dysgenetic chacma baboon

Behavioral studies of an XY gonadal dysgenetic chacma baboon under estradiol benzoate treatment were carried out. The dysgenetic individual and two ovariectomized conspecific control females were given a total of three testing series. The dysgenetic individual showed progressive success in her sexual interactions with her male partners and during her third testing series she was copulated with to ejaculation by five of the eight male partners. This study provides the first supportive evidence from a nonhuman primate for the predicted development of female sexual behavior in a genetic male deprived of testes prior to the sensitive period for sexual differentiation.     

Testosterone propionate treatment of an XY gonadal dysgenetic chacma baboon

Behavioral studies of an XY gonadal dysgenetic chacma baboon prior to and during testosterone propionate treatment were carried out. The orchidectomized dysgenetic individual, two intact males, a castrate male, and two ovariectomized females were pair-tested with a group of eight ovariectomized stimulus females prior to and during their treatment with estradiol benzoate. Three test series were carried out. One series occurred prior to any treatment of the agonadal focal subject animals. During this series it was only the intact males who showed behavior change during their testing with the estrogen treated females. A second test series occurred after a month of daily testosterone propionate injections (1 mg/kg/day) had been given to the four agonadal subjects. During this test series the castrate male ejaculated once with one of the estrogen-treated females. All of the treated subjects showed increases in their frequency of yawning. Upon completion of this test series the androgen dosage was increased (2 mg/kg/day) and 2 weeks later a third test series was carried out. During this series the castrate male ejaculated with five of his eight estrogen-treated partners. The yawning of all the treated subjects continued. As had been the case in the second series the XY gonadal dysgenetic individual continued to behave as did the ovariectomized females. None of these animals showed any increase in any measure of male sexual behavior. This study establishes the fact that a genetic male primate deprived of in utero exposure to testicular hormones will go on to develop as a normal genetic female and will fail to exhibit increased levels of male sexual behavior during androgen treatment.     

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.     

Subtrooping in a chacma baboon (Papio ursinus) population

Subtrooping in two baboon troops at Suikerbosrand, South Africa, was observed during a study of intertroop relations. Individual associations and locations were opportunistically recorded. Subtrooping varied in frequency according to season, being more frequent in the seasons with lower temperatures and food availability. Some subtroops frequented only certain parts of the larger troop range and remained separate from other groups for up to several days. Comparison with reports of subtrooping in other chacma populations reveals the study population to be relatively unique in the seasonality of subtrooping, the consistency of membership and the frequent occurrence of one-male subtroops. Lack of predation coupled with genetic isolation for several generations may have allowed the Suikerbosrand population to increase the efficiency of resource use in the less favorable seasons of the year, especially for less dominant individuals, through subtrooping. Subtrooping appears to be a facultative potential of all baboon species that requires little genetic change to develop.     

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.     

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.     

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.     

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.     

Progressions of adult male chacma baboons (Papio ursinus) in the moremi wildlife reserve

It has been suggested that the sociospatial organization of baboon progressions has a protective function in which the most physically powerful troop members, the adult males, play a key role. This theory implies regularities in adult male progression order for different species of savannah baboons with similar social systems. Quantitative progression data are available from two such similar baboon species, olive and yellow, but not from the third, chacma. The order of movement of 15 adult male chacma baboons was determined from 40 progressions observed at the Moremi Wildlife Reserve, Botswana. The chacma males were most often found in the front sixth of progressions, next most often in the second sixth, and about equally often from there to the rear. As expected from the protection theory, this frontal positioning is consistent with available quantitative data from other species of savannah baboons.     

The glomerular filtration rate,effective renal plasma flow,and renal blood flow in the adult male chacma baboon (Papio ursinus)

Abstract: The radionuclide determination of glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) has been validated in man, but not in the primate. GFR, ERPF, and renal blood flow (RBF) were measured in a group of 12 adult male chacma baboons using radiopharmaceuticals. GFR was determined using ^99mtechnetium-labelled diethylenetriamine-pentacetic acid. ERPF was measured with ¹³¹iodine-labelled hippuran. RBF, body surface area, and kidney weights were calculated using standard formulae. GFR was 49 ± 11 ml/min and ERPF was 237.9 ± 54.2 ml/min. Calculated RBF was 430.7 ± 111.9 ml/min and 507.4 ± 138.4 ml/min/100g of renal tissue. The results are in agreement with those obtained using more laborious nonradioisotopic techniques such as para-aminohippurate (PAH) and creatinine clearance and could serve as baseline normal values in the adult male chacma baboon.     

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.     

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.     

Diurnal variations in serum testosterone concentrations of captive adult male chacma baboons (Papio ursinus)

Captive adult male chacma baboons (Papio ursinus) housed with natural lighting exposure and blood sampled at 3-hr intervals showed significant diurnal variations in serum testosterone concentrations. Low mean concentrations were found at 0800 hr approximately 1 hr after sunrise and mean concentrations were their highest at 2000 hr approximately 1 ¼ hr after sunset.     

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.