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.     

Female perineal swelling and its effects on male sexual arousal: An apparent sexual releaser in the chacma baboon (Papio ursinus)

The function of the periodic perineal swelling that females of some primate species show in relation to their menstrual cycle has long puzzled many scientists. A role in female attractiveness was suspected, but fluctuations in female behaviors concomitant to these changes in female appearance have always prevented its assessment. By attaching a plastic reproduction of a fully swollen perineum to ovariectomized female chacma baboons, it has finally been demonstrated that the sexual swelling hasan important function in the sexual communication of this species. It induces sexual arousal in male conspecifics. The way the perineal swelling acts and other characteristic aspects of this feature appear to qualify it as a releaser for sexual behavior.     

Trade-offs in skillacquisition and time allocation among juvenile chacma baboons

We hypothesize that juvenile baboons are less efficient foragers than adult baboons owing to their small size, lower level of knowledge and skill, and/or lesser ability to maintain access to resources. We predict that as resources are more difficult to extract, juvenile baboons will demonstrate lower efficiency than adults will because of their lower levels of experience. In addition, we hypothesize that juvenile baboons will be more likely to allocate foraging time to easier-to-extract resources owing to their greater efficiency in acquiring those resources. We use feeding efficiency and time allocation data collected on a wild, free-ranging, non-provisioned population of chacma baboons (Papio hamadryas ursinus) in the Moremi Wildlife Reserve, Okavango Delta, Botswana to test these hypotheses. The major findings of this study are: 1. Juvenile baboons are significantly less efficient foragers than adult baboons primarily for difficult-to-extract resources. We propose that this age-dependent variation in efficiency is due to differences in memory and other cognitive functions related to locating food resources, as is indicated by the greater amount of time juvenile baboons spend searching for food. There is no evidence that smaller body size or competitive disruption influences the differences in return rates found between adult and juvenile baboons in this study. 2. An individual baboon’s feeding efficiency for a given resource can be used to predict the duration of its foraging bouts for that resource. These results contribute both to our understanding of the ontogeny of behavioral development in nonhuman primates, especially regarding foraging ability, and to current debate within the field of human behavioral ecology regarding the evolution of the juvenile period in primates and humans. Sara E. Johnson is Assistant Professor of Anthropology at California State University, Fullerton. She received her Ph.D. in Anthropology (Human Evolutionary Ecology) from the University of New Mexico in 2001. She uses behavioral ecology and life history theory to address her research interests in the evolution of primate and human growth; ecological variation and phenotypic plasticity in growth and development; ecological variation in life course trajectories, including fertility, health, morbidity, and mortality differentials; food acquisition and production related to nutrition; societal transofmration and roles of the elderly among indigenous peoples; and women’s reproductive and productive roles in both traditional and nontraditional societies. For the past decade she has conducted research on these issues in several different populations, including chacma baboons in the Okavango Delta of Botswana, two multiethnic communities of forager/agropastoralists in the Okavango Delta of Botswana, and among New Mexican men. John Bock is Associate Professor of Anthropology at California State University at Fullerton and is Associate Editor of Human Nature. He received a Ph.D. in Anthropology (Human Evolutionary EcologY) from the University of New Mexico in 1995, and from 1995 to 1998 was an Andrew W. Mellon Foundation postdoctoral fellow in demography and epidemiology at the National Centre for Epidemiology and Population Health at Australian National University. His recent research has focused on applying life history theory to understanding the evolution of the primate and human juvenile period. Bock has been conducting research among the Okavango Delta peoples of Botswana since 1992, and his current research there is an examination of child development and family demography in relation to socioecology and the HIV/AIDS epidemic. Other research is focused on health disparties among minorities and indigenous peoples in Botswana and the United States related to differential access to health care.     

Spatial structure of chacma baboon groups

A method is presented for measuring the location of individuals with respect to the center or perimeter of a primate group. The method estimates an individual’s domain of danger: the area in which a hidden predator is closer to the individual than to other group members (cf. Hamilton, 1971). A domain is determined by the directions and distances of particular neighbors from a given individual. Animals at peripheral locations have relatively large domains, whereas animals at central locations have relatively small domains. Domains of danger were sampled for members of two groups of chacma baboons (Papio ursinus)in northern Botswana, to test for nonrandom spatial patterns throughout the day. Females with infants had significantly smaller domains than did females without infants. Domains also were correlated with social ranks of females;high-ranking females had smaller domains than did low-ranking females, possibly because high-ranking females were more likely to have infant offspring. For adult males, however,domain sizes were not significantly correlated with social ranks. Immigration status of adult males, rather than social rank, better accounted for spatial positioning.     

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.     

Infanticide in a chacma baboon troop

This report describes an infanticide and two attacks of an infant and a juvenile by a natal adult male in a troop of chacma baboons (Papio ursinus). The infanticidal male had become the dominant male in his troop five months before the infanticide suggesting that a trigger for infanticidal behavior is a rise in rank to dominant status.     

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.     

Use of females by male olive baboons (Papio anubis)

Wild male olive baboons (Papio anubis) used females and infants as agonistic buffers. Male residency status determined whether a male used females or whether they were used against him. The success of the strategy depended on the cooperation of the female and the context of the interaction. Female cooperation correlated with preexisting social affiliation with the male user. Male choice of female or infant buffers represented a compromise between the potential effectiveness of each in different situations and the social and spatial availability of females and infants. Nonreproductive social relationships may provide long-term strategic benefits to the individuals who invest in them.     

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.     

Solitary male chacma baboons in a desert canyon

Solitary and paired adult (nine) and subadult (one) male chacma baboons, Papio ursinus, were observed over a period of years living in part of a wooded desert canyon not used by adjacent troops. These extratroop males were silent when alone and gave only one alarm vocalization, the “wa-hoo” call, when paired. The space occupied by them is unsuitable for use by troops according to criteria for adequate sleeping sites and access to water. But the foods available to them, especially figs, but also other fruits and fresh acacia seeds, were abundant. These foods are more highly preferred by baboons than those foods available to troop members. Troop members deplete these resources and shift to less preferred foods with lower water content and longer processing times. All of the adult members of the troop adjacent to these isolated males were infected with a skin disease. Isolated males were not so afflicted and so cannot have originated from, or ever been a part of, this troop. They probably moved to the space where they were observed from other inland troops, traveling to their current home range along the narrow canyon river course.     

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.     

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.     

Immigration of aPapio anubis male into a group ofPapio cynocephalus baboons and

The 1982 observation of the immigration of an adult male olive baboon, Papio anubis,into a group of yellow baboons, Papio cynocephalus,in Amboseli National Park, Kenya, constitutes the first confirmed report of interbreeding between the two species within the Amboseli baboon population. We document the social aspects of the immigration and describe subsequent sightings of anubisbaboons in Amboseli that confirm the existence of a previously unrecognized hybrid zone in Kenya.     

The gastrointestinal parasites ofPapio ursinus from the Drakensberg Mountains,Republic of South Africa

One hundred twenty-two fecal samples were collected from two troops of chacma baboons (Papio ursinus),living in montane and subalpine grassland, trespectively. These were examined for the presence of gastrointestinal parasites. Five protozoan, six nematode, and two cestode species were identified. Identifications were based on the morphology of cysts in the case of Protozoaand of eggs in the case of helminths. Strongyle nematodes were tentatively identified on egg size ranges and larval characteristics.     

Observations on the ascending aortic fold in two chacma baboons (Papio hamadryas ursinus)

Baboons (Papio) were used to study the ascending aortic fold. The fold was present in two out of 20 hearts examined. Its position and shape was comparable to that observed in human subjects. The principal difference was the absence of paraganglia. The functional role of the baboon fold is unclear.     

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.