New record of predatory behavior by the mandrill in Cameroon

The predatory behavior of the mandrill (Mandrillus sphinx,Linnaeus 1758), a forestliving baboon, on the bay duiker (Cephalophus dorsalis,Gray 1864) was observed under natural conditions. In the predatory episode, at least two mandrills (one adult female and one adult male) attacked a bay duiker, but no overt aggressive interactions between the attackers occurred during consumption. The estimated predation pattern based on scars—intensive attacking of the head and pulling of the hind legs to eat the thigh muscles first—resembled the predation patterns of captive mandrills observed experimentally. The findings suggest that the predatory behavior is established in mandrills as a feeding behavior pattern as in savanna-living baboons. New data are thus presented which are relevant to the discussion of the origins of hunting behavior in early hominids.     

Agonistic dominance in male baboons: An alternative view

Data on baboons have generated both the concepts normally associated with male dominance hierarchies among primates and the tests of their significance. The priority-of-access model has been used to predict the relationship between dominance rank and resource acquisition. While the correlation between these two factors, or between rank and measures of reproductive success, has varied among different primate species, most recent baboon field-workers have interpreted their results to be consistent with the model. Based on 1200 hr of observation of a troop of savannah baboons near Gilgil, Kenya, this paper presents data on male agonistic interactions and on male acquisition of resources. Predictions of the priority-of-access model are tested and an inverse relationship is found between agonistic dominance rank and acquisition of two limited resources, estrous females and meat. The importance of the residency status of males is explored and an alternative hypothesis is presented to account for the anomalous pattern in the data. The relationship of male reproductive success and dominance rank is evaluated in light of the data on these baboons and the “residency” hypothesis.     

Demographic consequences of a food and water shortage to desert Chacma Baboons,Papio ursinus

The age-sex composition of a chacma baboon (Papio ursinus)population changed following a 5-month interval of extreme food and water shortages. Mortality was significantly greater among adult females, juveniles, and infants than among adult males. The probable basis of 19 of 22 deaths during the interval of food and water shortage was starvation caused by drought conditions which localized water sources, reducing access to food resources. This resulted in a long-term (> 6-year) shift in adult sex ratios within this three-troop population, from 1.04 to 1.42-1.58 adult and subadult males per adult female. Patterns of intertroop interaction were also influenced by food scarcity, which determined which troop was most seriously affected.     

The behavioral ecology of mountain baboons

Chacma baboons (Papio ursinus)were studied in a mountain habitat where the effects of high altitude and latitude combine to produce conditions as harsh as those experienced by the desert or hamadryas baboon (P. hamadryas).The population density was as low as that of hamadryas baboons. A survey of populations at altitudes between 1400 and 3000 m showed a strong negative correlation between altitude and group size, with the highest-living groups averaging just 13 individuals and, like hamadryas baboons, seasonally retreating from marginal habitat on the fringes of the range. Foraging activities in these groups relied heavily on the underground storage organs of plants and other items that were time-consuming to find, harvest, and process, placing severe constraints on the time budget. High-altitude and low-altitude groups were nevertheless able to maintain similar activity budgets. This is explicable through an interaction between the patterns of foraging and range usage and observed altitude differences in group size, population density, and home-range size. The behavior of mountain baboons provides insights into ecological effects on behavior both through local altitudinal variation and through similarities to other populations inhabiting marginal environments, notably P. hamadryas.Mountain baboons may represent a significant southern highland population which does not fit into the neat socioecological dichotomy of desert versus savannah baboons.     

Continued decline in tree euphorbias (Euphorbia tetragona and E. triangularis) on the Great Fish River Reserve,Eastern Cape,South Africa

A dramatic decline averaging 43% over a 4‐year period has occurred in tree Euphorbia (Euphorbia tetragona and Euphorbia triangularis) populations on the Great Fish River Reserve, South Africa. These changes are evident from data gathered by general vegetation monitoring methods as well as from a focused study of four tree Euphorbia populations. The decline from 2003 to 2007 was more marked for E. triangularis than for E. tetragona and was accompanied by a general absence of seedlings and a reduced presence of younger age classes of both species, decreasing the proportion of younger trees in the populations. The role of megaherbivores, specifically the black rhinoceros, in these changes is well established. However, the impact of baboon activity, leading to damage to tree crowns and upper branches, is also substantial, especially on E. triangularis populations. Damaged crowns were recorded significantly more often for E. triangularis than for E. tetragona, and the damage frequency increased with decreasing tree height. Thus, our work provides the first evidence that these two closely related Euphorbia species may be affected differently by herbivory.     

Bone ALP and OC reference standards in adult baboons (Papio hamadryas) by sex and age

BACKGROUND: Serum bone-specific alkaline phosphatase (bone ALP) and intact osteocalcin (OC) are markers of bone formation of interest because of easy measurability and potential utility as identifiers of those at risk for fractures associated with bone metabolism disorders. The baboon (Papio hamadryas) exhibits extensive biological similarities to humans making it particularly well suited to studies of bone maintenance and turnover. METHODS: We measured serum bone ALP and OC in 591 baboons. RESULTS: We report significant sex and age effects and present reference ranges and percentile distributions for these markers. CONCLUSIONS: This study is the first to characterize normal variation in bone ALP and OC levels in baboons and to assess the age and sex effects on this variation. The results provide much-needed reference standards to allow researchers to evaluate the status of their animals in cross-sectional studies and assess the meaning of changes in bone ALP and OC levels in longitudinal studies.