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 waning of dependence in infant free-ranging yellow baboons (Papio cynocephalus) of Mikumi National Park

Development toward independence during the early years of baboon life is reflected in the infant's transition from riding on its mother to walking on its own during progressions from one location to another. This transition was studied during the first year of life in 55 infants from two differently sized troops living in Mikumi National Park, Tanzania. There was a nearly linear transition in the first year from almost 100% ventral riding to almost 100% walking. The amount of dorsal riding started near zero, reached a plateau lasting from about the 15th to the 26th wk of life, and then gradually declined to zero. Dorsal riding did not replace ventral; rather, dorsal riding increased in frequency until it occurred about as often as ventral riding. Prolonged ventral riding by infants of the smaller of the two troops may have been due to spacing differences or to greater nervousness among members of the smaller troop. There were no significant differences in riding or walking associated with the time of day or the infant's sex. The rate of transition from riding to walking was greatest from about the fifth to the seventh months, which may be especially significant time in the early development of independence.     

Radioimmunoassay of somatomedin-C in the baboon (Papio cynocephalus): A comparison of multiple techniques of measurement

This study was undertaken to assess the nature of somatomedin-C (SM-C) in baboon (Papio cynocephalus) blood and to compare various methods for estimating SM-C concentrations. Parallel dose-response curves were obtained with normal baboon serum, normal human serum, and purified SM-C. Recovery of purified SM-C added to baboon serum over a wide dosage range (n = 17) was 111 ± 12%, with slightly better recovery at higher potencies. Chromatography of normal baboon serum on Sephadex G-200 at neutral pH produced a profile similar to that observed in the human, as did samples chromatographed on Sephadex G-50 in acid. Although the SM-C content in acid chromatographed plasma was approximately 2.5 times higher than in native unprocessed plasma, there was excellent correlation between the values (r = 0.9143, p < 0.0001). The SM-C in baboon plasma which had been preincubated with glycine HCl was approximately twice that of unprocessed plasma, but the correlation between the two methods was excellent (r = 0.9593, p < 0.0001). The correlation between values obtained after simple acid-ethanol extraction and those observed in unextracted plasma were also significant (r = 0.7689, p < 0.0001). Following a series of four injections of human growth hormone (hGH) to a normal baboon, plasma SM-C rose approximately sevenfold above the initial concentration and returned to basal levels five days after the final injection. These studies show that although the radioimmunoassay (RIA) for SM-C in unprocessed baboon plasma does not measure all of the SM-C present, it provides a reliable index of the total SM-C concentration and reflects GH status in the baboon.     

Movement patterns of yellow baboons (Papio cynocephalus): Central positioning of walking infants

According to DeVore and Washburn's protection theory of the spatial organization of moving baboon troops, walking infants, which are among the most vulnerable and least self-sufficient of all troop members, should tend to occupy the troop's center. The protection theory is an ultimate hypothesis from which persistently recurring behavior is expected. Two troops living in Mikumi National Park, Tanzania, were compared with troops studied at other locations. Walking infants tended to occupy the center of their troop and to be underrepresented primarily in the frontal portion of progressions and secondarily in the rear. The lead position of progressions was analyzed using 82 walking infants, 11 troops, three locations, two species, and three studies involving eight or more observers employing somewhat different procedures at the different study sites. Despite so many opportunities for variation, 1,317 observations from these 11 troops did not produce a single instance in which a walking infant led the troop and very few in which one was in the frontal twelfth.     

Pasteurella multocida infections in baboons (Papio cynocephalus)

The respiratory pathogenPasteurella multocida was isolated from infections of the laryngeal air sacs of two baboons and from abscesses in the neck or femoral area of two other baboons. The infections were associated with surgical procedures involving the cervical area, chronic catheterization, and chair restraint. The organism was also detected among the commensal pharyngeal flora in 2 of 15 clinically healthy, wildborn adult baboons. These findings suggest that the organism is harbored naturally in baboons and that exudative infections can occur secondary to specific procedures.     

Weaning of free-ranging infant baboons (Papio cynocephalus) as indicated by one-zero and instantaneous sampling of feeding

Weaning from the nipple and the use of solid foods were studied by one-zero and instantaneous sampling during the first year of life for 46 baboon infants. By the end of 1 year, infant baboons were nearing independence from the mother for nourishment and transportation and were competently foraging for insects and several plant foods. Using on-nipple as an index of waning dependence and the transition from riding on the mother to walking as a validity criterion, the two sampling methods yielded comparable scores which were valid indicants of developing independence.     

A cytogenetic survey of 110 baboons (Papio cynocephalus)

A cytogenetic investigation of 110 adult baboons (Papio cynocephalus) captured in Kenya and sacrificed at the Institut Pasteur, Paris, showed the absence of anomalies, numerical or structural bearing on nonheterochromatic material; a polymorphism of the AgNOR-positive secondary constriction of chromosome 5 in 12% of the animals; a polymorphism of a secondary constriction of chromosome 7 in 2% of the animals; a fragile site of chromosome 6 in one animal. We believe that our data show that cytogenetic observations in present day primates probably reflect their chromosomal evolution.     

Plant feeding of yellow baboons (Papio cynocephalus) in Mikumi national park,Tanzania, and the relationship between seasonal feeding and immature survival

Focal-animal feeding data obtained from 64 adult baboons during a 3-year period were used together with equivalent data from 46 infants to evaluate hypotheses predicting selection for a birth peak and to study the baboon’s eclectic/selective feeding adaptation, with emphasis on differential feeding by sex, developmental trends, and seasonal use of food classes (fruit, leaf, flower, grass, etc.). The findings suggest that feeding conditions are better in the wet season than in the dry season. Despite large sexual dimorphism, estimates of total amounts eaten were virtually identical for males and females. Infants used all of the same plant-food classes as adults, but proportional differences occurred for some food classes in amounts eaten. Foods eaten proportionately less by infants were probably harder for them to obtain and process or were chosen through inexperience or for exploration. There was considerable between-year variation in amounts of food classes eaten, but the within-year standard deviations were similar, as were also the mean amounts eaten per year. An eclectic/selective feeding adaptation has the advantage of permitting long-run acquisition of adequate nutrition within a context of high feeding variation from season to season and year to year. Mixed results were obtained from hypotheses about selection for a birth peak. Although a peak occurred in the early dry season, this was not the optimal time of birth for survival. Survival was highest for individuals born in the late wet season, when the availability and probably the quality of food for lactating mothers were greatest.     

Can Concurrent Speed and Directness of Travel Indicate Purposeful Encounter in the Yellow Baboons (Papio hamadryas cynocephalus) of Ruaha National Park,Tanzania?

I used components of baboon foraging behavior (concurrent fast and direct travel) to categorize core dry-season foods as purposefully or randomly encountered. I then compared the categorized foods to published, a priori predictions for core dry-season foods. Using focal-animal techniques on 6 males from two baboon troops, I collected precise locational data with a differentially corrected Global Positioning System (GPS) over 6 mo. The data analysis yielded the speed and directness of baboon travel between a food-handling event and a prior location. To distinguish purposefully encountered foods from randomly encountered foods, I calculated the average speed and the average observed deviation from straight-line travel exhibited to each resource type. A linear regression describes the relationship between these variables for each resource type. Baboons demonstrate both relatively high speeds and direct travel towards 3 food types: Combretum obovatum, impala, and baobab trees. Baboons were hypothesized a priori to encounter these resources purposefully. Baboons were also hypothesized a priori to encounter corms and perhaps Commiphora paniculatum purposefully, however, they travel neither quickly nor directly to these resources. I interpret this finding in terms of the costs accrued by traveling quickly and directly to fall-back resources. I discuss the ability of concurrent speed and directness to distinguish purposefully encountered foods from randomly encountered foods.     

Failure of the prostaglandin F2 alpha analogue, cloprostenol, to induce functional luteolysis in the olive baboon (Papio cynocephalus anubis)

The prostaglandin F2 alpha analogue, cloprostenol, which is an effective luteolytic agent in the common marmoset, was administered intramuscularly to olive baboons to determine if it possessed luteolytic properties in this species. The results showed that functional luteolysis was not induced when cloprostenol was administered during the mid- to late luteal phase or during early pregnancy.     

The relationship between altitude and group size in mountain baboons (Papio cynocephalus ursinus)

Twenty-seven troops were counted during a 1989 census of the mountain baboon population at Giants Castle Game Reserve. In contrast to earlier findings, and despite a similar population structure, we found no relationship between group size and altitude. We argue that this is a consequence of long-term population processes whereby groups split as they grow larger and, in some cases, as their home ranges expand upward. At these high altitudes, smaller groups are eventually subjected to environmental conditions that destroy them. We propose that the high-altitude slopes act as a demographic sink.     

Gastro-intestinal helminth parasites of the chacma baboon, Papio cynocephalus ursinus, from the coastal lowlands of Zululand, South Africa

An examination of 191 faecal samples from Papio cynocephalus ursinus from Mkuzi Game Reserve, Natal, South Africa, has revealed low prevalence rates for a high diversity of gastro-intestinal helminths. This high diversity, including the first evidence for an acanthocephalan infection in South African baboons, is compared to that from montane baboons studied previously.     

Microsatellite Variation in Two Populations of Free-Ranging Yellow Baboons (Papio hamadryas cynocephalus)

We investigated genetic variation at six microsatellite (simple sequence repeat) loci in yellow baboons (Papio hamadryas cynocephalus) at two localities: the Tana River Primate Reserve in eastern Kenya and Mikumi National Park, central Tanzania. The six loci (D1S158, D2S144, D4S243, D5S1466, D16S508, and D17S804) were all originally cloned from and characterized in the human genome. These microsatellites are polymorphic in both baboon populations, with the average heterozygosity across loci equal to 0.731 in the Tana River sample and 0.787 in the Mikumi sample. The genetic differentiation between the two populations is substantial. Kolmogornov–Smirnov tests indicate that five of the six loci are significantly different in allele frequencies in the two populations. The mean F _ST across loci is 0.069, and Shriver's measure of genetic distance, which was developed for microsatellite loci (Shriver et al., 1995), is 0.255. This genetic distance is larger than corresponding distances among human populations residing in different continents. We conclude that (a) the arrays of alleles present at these six microsatellite loci in two geographically separated populations of yellow baboons are quite similar, but (b) the two populations exhibit significant differences in allele frequencies. This study illustrates the potential value of human microsatellite loci for analyses of population genetic structure in baboons and suggests that this approach will be useful in studies of other Old World monkeys.     

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.     

Gastrointestinal Parasites in Free-Ranging Kenyan Baboons (Papio cynocephalus and P. anubis)

We screened fecal samples from 3 groups of wild-living baboons (Papio cynocephalus and P. anubis), involved in longitudinal behavioral studies, for evidence of gastrointestinal parasites. The two objectives of the study were: 1) to compare parasites from two of the groups with different foraging behavior from the same area and 2) to obtain fecal parasitic data on 3 groups of baboons to provide baseline reference data. We sampled individual baboons opportunistically from Lodge and Hook's groups, Amboseli National Park and from Mpala Group, Mpala Wildlife Research Centre, Kenya. Lodge Group baboons supplemented foraging on wild foods by daily foraging in human-source refuse, whereas Hook's and Mpala groups did not. We collected fecal samples from 55, 30 and 42 individuals in Hook's, Lodge and Mpala groups, respectively, and processed them via ether sedimentation. We identified strongylids, Streptopharagus sp., Physaloptera sp., Trichuris sp., Enterobius sp., and Strongyloides sp., in the feces, but no parasite directly attributable to exposure to people. Garbage- and wild-feeding Amboseli baboons differed in the prevalence of Streptopharagus sp., Physaloptera sp. and Trichuris sp.     

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.