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.     

Alveolar bone loss in wild baboons

Radiograph-based methods were used to assess alveolar bone loss in 12 juvenile and 18 adult baboons (Papio hamadryas, sensu lato) living in the Awash National Park, Ethiopia. Alveolar bone loss, as measured from the cementoenamel junction to the alveolar crest, averaged about 1 mm in juveniles and about 1.5 mm in adults. Densitometry of alveolar bone from the radiographs provides a baseline for comparisons with other adult baboons. Periodontal disease surveys of baboon populations using such methods may identify potential etiological agents. Such knowledge may contribute to a better understanding of periodontal disease etiology in humans. © 1993 Wiley-Liss, Inc.     

Body mass and growth rates in a wild primate population

Summary We obtined data on body mass and growth rates for the immature members of two groups of wild baboons in Amboseli National Park, Kenya. Data were collected without feeding, trapping, or handling. The data were separated into cross-sectional and longitudinal components, allowing both the examination of body mass-age relationships and the calculation of growth rates for individuals. For animals less than three years old, body mass was wellperedicted from age by a linear model. Differences based on social group membership were small but consistent, and their origins are discussed. We detected no differences in body mass based on sex or on maternal dominance rank. For older juveniles, those three to seven years of age, a better fit was obtained from log of mass than by mass in a linear model. This was also true for the cross-sectional data set over the whole age range (zero to seven years). For older juveniles, samples were too small for quantitative analysis of differences based on sex, rank, or group membership, but trends in the data are indicated. Growth rates derived from repeat measures of body mass for 38 animals are presented and discussed.The growth rate values obtained in this study are consistent with data from cross-sectional studies of other wild baboon populations; these values for wild baboons are consistently one-half to one-third lower than growth rate values for well-provisioned captive baboons and equivalent to captive baboons fed a low-protein diet. Comparisons between primates and other mammals in the primate size range raise questions concerning ecological and behavioral constraints on primate growth rates; some possible mechanisms of constraint are suggested.     

Effects of food availability on serum insulin and lipid concentrations in free-ranging baboons

The relationship between food availability and metabolic physiology was studied in groups of free-ranging baboons (Papio spp.) living in the Amboseli National Park and the Masai Mara National Reserve of Kenya. Three groups subsisted entirely on natural forage, while two other groups lived near tourist facilities and often consumed food wastes from these lodges. The refuse provided a very accessible food source with relatively high caloric density. Consumption of the refuse was associated with reduced locomotion. Sexually mature individuals from all five groups were sedated surreptitiously in the early morning and blood samples were collected. Compared to animals foraging exclusively in the wild, animals that supplemented their diet with the refuse items had two- to threefold elevations in serum insulin concentrations, as well as increased total cholesterol (C), HDL-C, and VLDL+LDL-C levels. No sex differences in physiological measures were observed except in body mass. Elevated serum insulin, and cholesterol and lipoprotein concentrations influence the development of cardiovascular disease and have been shown to be subject to dietary manipulation and exercise under controlled conditions. The present results suggest potentially deleterious effects of a highly accessible, calorically dense food source, and associated reduction of physical activity for baboons living in an otherwise natural environment.     

Hepatocystis in populations of baboons (Papio hamadryas s.l.) of Tanzania and Ethiopia

Bloodsmears from 119 yellow baboons (Papio hamadryas cynocephalus) in six groups in Mikumi National Park, Tanzania, and from 189 olive (P.h. anubis) hamadryas (P.h. hamadryas) and hybrid baboons in three groups in Awash National park, Ethiopia showed differing levels of infection with Hepatocystis simiae. 0% to 42% in the Tanzanian groups were carriers of the parasite but none of the Ethiopian baboons was positive. The remarkable absence of H. simiae in the Ethiopian baboons is believed to be related to environmental factors that exclude transmission in the absence of the Culicoides vector.     

Life history of yellow baboons: Physical development,reproductive parameters,and infant mortality

Longitudinal data from a population of yellow baboons,Papio cynocephalus, in the Amboseli National Park, Kenya, provide life history parameter estimates. Females reached menarche at approximately four-and-a-half years of age and then cycled for approximately a year before first conception. Postpartum anestrum averaged 12 months but ranged from six to 16 months. In cases of still births or infant death during postpartum amenorrhea, females commenced cycling after approximately one month. In mature females the time spent cycling before conception was five months on the average with a range from one to over 18 months. Only half of all full-term pregnancies resulted in infants who survived the first year of life; only a third, in infants who survived until the birth of their mother’s next infant. In comparison with data from laboratory colonies, our data indicate that female baboons in Amboseli are older at birth of first infant. They have, on the average, a somewhat shorter interbirth interval than was estimated from earlier crossectional field data, and therefore spend a larger portion of their adult life pregnant, but have a much longer interval—at least three years on the average—between the birth of an infant and the birth of that infant’s next older surviving sibling. A number of morphological changes in immature baboons are described.     

Alternation of sleeping groves by yellow baboons (Papio cynocephalus) as a strategy for parasite avoidance

The primary locus of contact between free-living yellow baboons (Papio cynocephalus) in the Amboseli National Park of Kenya and the infective stages of their intestinal parasites is believed to be soil beneath sleeping trees contaminated by the baboons' own fecal emissions. In this report, we present evidence both that infective ova and larvae of intestinal parasites are found at very high densities in the soil beneath sleeping groves and that Amboseli baboons substantially reduce their contact with this reservoir of parasites by alternating periods of a few consecutive nights' use of any particular grove with much longer periods of avoidance of that grove. Although many factors other than the presence of parasite larvae also influence choice of sleeping groves, we propose as a working hypothesis that the temporal pattern of sleeping grove alternation shown by Amboseli baboons reflects a subtle behavioral strategy for parasite avoidance.     

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.     

Some developmental markers in yellow baboon infants of Mikumi National Park,Tanzania

Infants of known birthdates were sampled from a population of yellow baboons (Papio cynocephalus) in Mikumi National Park, Tanzania, to ascertain the reliability of several maturational changes which could be used to age infants whose birthdates are unknown. The transition from the infant's black natal coat to the uniform yellow or tan adult pelage proved extremely variable, with completion varying from 7 to 19 months. The transition from the pink skin of the newborn to the completely grey adult pigmentation was much less variable. Skin on the hands and feet and on the paracallosal area was completely grey in all individuals by 8 months, while skin on the face and ears changed more gradually and was entirely grey by 12 months. These data are in substantial agreement with maturational markers established for yellow baboon infants in Amboseli National Park, Kenya, despite differences in habitat and age-sex structure between the two populations.     

Secondary sex ratio and maternal dominance rank among wild yellow baboons (Papio cynocephalus) of Mikumi National Park,Tanzania

The Trivers and Willard model predicts that offspring of dominant mothers will be biased toward males and offspring of subordinate mothers towards females, whereas a local-resource-competition hypothesis predicts the reverse. Available data bearing upon these alternative predictions are inconsistent. It has been suggested that the local-resource-competition hypothesis will predominate when resources are scarce, and the Trivers-Willard hypothesis when resources are abundant. The relationship between maternal dominance and secondary sex ratio for 214 offspring of 61 females was examined using four troops of wild yellow baboons living in Mikumi National Park, where the population was increasing in a resource-rich habitat. For all troops combined, no significant relationship was found between offspring sex ratio and maternal rank. The four troops separately showed inconsistent trends, and in no case did the relationship reach conventional levels of statistical significance. In contrast, the local resource-competition hypothesis was supported by a study of yellow baboons done with one troop and 80 offspring in Amboseli National Park, where a massive population decline had occurred. The contrasting Amboseli and Mikumi results may be due to differences in resource-competition at the two study sites, or to stochastic variation. © 1992 Wiley-Liss, Inc.     

Correlates of agonistic and competitive interactions in pregnant baboons

Maternal condition during pregnancy is known to influence fetal viability. Recently, primatologists have suggested that certain characteristics of the fetus may influence maternal condition as well. For example, among captive pigtailed macaques (Macaca nemestrina) mothers of female infants may be at greater risk of injury during their pregnancies than mothers of male infants. Analysis of the rates of aggression, submission, competition, and wounding among free-ranging pregnant baboons (Papio cynocephalus) in Amboseli National Park generally fail to support these findings, but several other factors such as maternal dominance rank, environmental conditions during pregnancy, maternal parity, and fetal age correlate with aggression, submission, competition, and injuries sustained by pregnant female baboons.     

Demography of Amboseli baboons, 1963–1983

Repeated censuses of a population of yellow baboons (Papio cynocephalus) in Amboseli National Park, Kenya, revealed a decrease from over 2,500 animals in 1963–1964 to 123 individuals in 1979, or from a density of about 73 to 1.8 baboons per km² over a 15-year period. Median group size decreased from 43 in 1964 to 27 in 1979. The largest and smallest groups declined the most; groups near the median have maintained fairly stable size and age distributions. The population seemed to have stabilized by 1983 at approximately 150 animals in six groups (median group size 28; density 2.2/km²). Although baboon population and group size appeared to be stable during 1963–1964, the age distribution and demographic parameters (age-specific mortality and natality for one social group) during that year indicate that the population decline had already started. The rate of population decline was greatest in the 1964–1969 period and remained appreciable during the next 5 years. The decline of the baboon population was paralleled by that of other Amboseli savannah woodland mammalian species and took place during a period of very high mortality of fever trees (Acacia xanthophloea) and extensive invasion of the area by halophytes, a transition brought on by rising ground water and consequent elevation of the soil salinity zone. In this and several other primate populations, mortality of infants and juveniles appears to be the demographic variable most sensitive to environmental change.     

Resource base,parity, and reproductive condition affect females' feeding time and nutrient intake within and between groups of a baboon population

Summary We examined within- and between-group differences in aspects of feeding and nutrient intake among adult females of a single population of baboons (Papio cynocephalus) in Amboseli National Park, Kenya. Differences in time spent feeding, daily energy and protein intake and feeding efficiency (nutrient intake per minute spent feeding) reflected differences in resource base, reproductive condition and parity. Baboons that partially fed from a lodge garbage dump spent less than half the time feeding than those that were feeding totally in the wild. During this greatly reduced feeding time, the garbage-feeding group had a similar daily energy intake and only a slightly lower daily protein intake relative to wild-feeding baboons. Consequently, the feeding efficiency of the semi-provisioned baboons was appreciably higher than that of the non-provisioned baboons. For the totally wild-feeding baboons, samples were large enough to permit analyses of feeding time and nutrient intake during different reproductive states and parity. Females spent more time feeding and had higher daily energy and protein intake when they were pregnant or lactating than when they were sexually cycling. Nulliparous females spent more time feeding than their multiparous counterparts. The daily energy intake of nulliparous females was higher than that of their multiparous counterparts, but their daily protein intakes did not differ significantly. Pregnant or lactating and nulliparous females had higher feeding efficiency than their sexually cycling and multiparous counterparts. The two nulliparous females in the garbage-feeding group spent more time feeding but did not take in more energy or protein per day than their multiparous counterparts.     

Hominid tool-making versus carnivore scavenging

The effects of hyena scavenging on the remains of 75 animals in the Awash National Park, Ethiopia, were examined to provide a modern analogy to the fossil assemblage from Makapan. Brain's recent work ('70, '76) suggests that the actions of carnivores may account for the characteristics of the Makapan assemblage, a theory which contrasts with Dart's ('49, '55, '57, '59) interpretation of the fossils as osteodontokeratic tools and weapons manufactured, collected, and used by australopithecines. The modern assemblage was like that from Makapan in terms of relative representation of skeletal elements and patterns of bone breakage. Observations of hyenas in the Awash also lend support to the hypothesis that the Makapan assemblage may represent the uneaten remains of carnivore kills. The representation of major vertebrate groups at Makapan was compared with their representation at Awash and with their representation in hyena diets in the Serengeti and Ngorongoro Crater (Kruuk, '72). This technique of faunal analysis was unable to detect differences between these groups, despite the fact that the three modern assemblages represent animals that died of different causes. Thus extreme caution must be used in deducing any specific information about the mode of death or taphonomic history of the animals represented in an assemblage on the basis of such faunal analyses.     

Feeding ecology of Lilian’s Lovebird Agapornis lilianae in Liwonde National Park,Malawi

Lilian's Lovebird Agapornis lilianae is a small, near-threatened parrot resident in mopane Colophospermum mopane woodlands. We investigated its diet and foraging behaviour in Liwonde National Park, Malawi. We expected that Lilian's Lovebirds would show little specialisation for a particular food source but generally feed on available seeds, fruits, flowers and other items as observed in other lovebirds. Lilian's Lovebirds fed on 30 different plant species. Lilian's Lovebirds were observed feeding in six habitat types in Liwonde National Park and adjacent areas during the wet season, and four in the dry season. In the wet season lovebirds (23% of observations) foraged in grassy wetland (dambo) areas the most, whilst in the dry season they foraged in grasslands with tree cover (18%) the most. In mopane woodland, foraging flock sizes differed significantly between the wet (mean = 19.8 ± 1.0 lovebirds) and dry season (mean = 33.6 ± 2.3 lovebirds). Grass seeds were lovebirds’ main food source from December to June. The nutritional analysis of preferred foods showed that grass seeds have a relatively high protein and energy content. Grass seed availability is reduced with savanna burning and so early season burning (before May–June) in areas in and outside the park is not recommended.     

Ecology and sociality in a multilevel society: ecological determinants of spatial cohesion in hamadryas baboons

The multilevel society of hamadryas baboons, consisting of troops, bands, clans, and one-male units (OMUs), is commonly perceived to be an effective means of adapting to variable food availability while allowing spatial cohesion in response to predator pressure. The relationship between these variables, however, has never been tested quantitatively. The Filoha site in Awash National Park, Ethiopia is ideally suited to such an investigation as it contains nutrient-dense palm forests in addition to the Acacia scrublands typical of hamadryas distribution elsewhere, allowing comparisons of spatial cohesion across habitat types. Here, we use observations over a 1-year period to examine the relationship between resource availability, perceived predator pressure, and spatial cohesion in a band of wild hamadryas baboons at Filoha. Our results demonstrate that the band was more likely to break into OMUs when foraging in habitats with lower food availability, and that the band fissioned into independent clans more often when preferred resources were not available. Furthermore, the baboons remained in larger aggregations for longer periods of time (i.e., prior to embarking on their daily foraging route) on mornings after predators were heard in the vicinity, and increased cohesion in response to encounters with people who may have been perceived as predators. These results support the notion that hamadryas baboons change their social groupings in response to both food availability and predation risk and that the ability of hamadryas bands to cleave and coalesce in response to changes in these factors underlies the evolution of the hamadryas modular social structure.     

Physical maturation and age estimates of yellow baboons,Papio cynocephalus,in Amboseli National Park,Kenya

In a longitudinal study of individually identified wild baboons in Amboseli National Park, Kenya, we collected data on physical development and reproductive maturation. Confirming and extending our earlier results, we demonstrated that the ratio of ages at which developmental milestones occur in the field as compared to those under extensive provisioning or in captivity were approximately 5:3. The age range for some developmental milestones was quite narrow and discrete, while for others there was considerable between-individual variability and more gradual changes. For infants, only the change from pink to gray of the paracallosal skin occurred within a brief age span. For older animals two important developmental events are readily identified and occur within a fairly narrow age range: Rapid enlargement of testes at 5 to 6 years for males and onset of menarche at 4 to 5 ½ years for females. In the present report, we considered some consequences of accelerated or delayed maturation. We further explored the need to employ different age-class criteria for different research problems.     

The sociality of nesting in Rüppell's Weaver Ploceus galbula and the Lesser Masked Weaver Ploceus intermedius in an Ethiopian acacia woodland

Rüppell's Weaver Ploceus galbula and the Lesser Masked Weaver Ploceus intermedius nest prominently in the Awash National Park, Ethiopia. In both species the sociality or degree of aggregation of their nesting is varied. Rüppell's Weaver can nest singly or in small clusters, or in association with the Lesser Masked Weaver, which itself can nest in loose aggregations or bustling colonies. This variation suggests a continuum of nesting sociality in weavers, from solitary nesting through associative and gregarious nesting to full coloniality.     

Out of the mouths of baboons: stress,life history,and dental development in the Awash National Park hybrid zone,Ethiopia

The techniques of dental histology provide a method for reconstructing much of the life history of an individual, as accentuated increments visible in polarized light microscopy record incidents of physiological stress during the formation of dental tissues. Combined with counts of the normal periodic growth increments, they provide a means of reconstructing the chronology of dental development, age at death, and the ages at which stress occurs. In this study, we determine age at death and reconstruct the chronology of dental development in two male anubis baboons from Uganda and two female baboons from the Awash National Park hybrid zone. For the female baboons, we used the dates of death and rainfall records for the region to determine date of birth, ages at periods of physiological stress, dates at which these stresses occurred, and rainfall amounts for those months.Ages determined histologically for each specimen are comparable to ages estimated from dental emergence schedules and dental scores for wild baboons. Crown formation times are longer than those reported in radiographic studies of captive yellow baboons. Age at initiation of crown formation is similar to that reported for radiographic studies, but ages at completion of crown formation are consistently later. The pattern of stresses is similar in the two female baboons, suggesting that individual life history intersects with local ecology to produce a pattern of accentuated increments occurring during the weaning process and at the onset of menarche, as well as during the first postweaning dry and rainy periods.     

Genetic evidence reveals temporal change in hybridization patterns in a wild baboon population

The process and consequences of hybridization are of interest to evolutionary biologists because of the importance of hybridization in understanding reproductive isolation, speciation, and the influence of introgression on population genetic structure. Recent studies of hybridization have been enhanced by the advent of sensitive, genetic marker-based techniques for inferring the degree of admixture occurring within individuals. Here we present a genetic marker-based analysis of hybridization in a large-bodied, long-lived mammal over multiple generations. We analysed patterns of hybridization between yellow baboons (Papio cynocephalus) and anubis baboons (Papio anubis) in a well-studied natural population in Amboseli National Park, Kenya, using genetic samples from 450 individuals born over the last 36 years. We assigned genetic hybrid scores based on genotypes at 14 microsatellite loci using the clustering algorithm implemented in STRUCTURE 2.0, and assessed the robustness of these scores by comparison to pedigree information and through simulation. The genetic hybrid scores showed generally good agreement with previous morphological assessments of hybridity, but suggest that genetic methods may be more sensitive for identification of low levels of hybridity. The results of our analysis indicate that the proportion of hybrids in the Amboseli population has grown over time, but that the average proportion of anubis ancestry within hybrids is gradually decreasing. We argue that these patterns are probably a result of both selective and nonselective processes, including differences in the timing of life-history events for hybrid males relative to yellow baboon males, and stochasticity in long-distance dispersal from the source anubis population into Amboseli.