Knuckle walking by a baboon (Papio cynocephalus).

This paper describes the development of a knuckle walking mode of locomotion by a free-living yellow baboon (Papio cynocephalus). Some implications of this occurrence for theories of the evolution of knuckle walking are discussed.     

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.     

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.     

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.     

Movement patterns of yellow baboons (Papio cynocephalus): Sex differences in juvenile development toward adult patterns

Age-sex differences in the sociospatial positioning of progressing baboon troops have been postulated as an important, protective aspect of baboon adaptation to a terrestrial existence. The protection theory is an ultimate hypothesis which can be disproven by showing that the postulated age-sex positioning fails to occur. Alternatively, confidence in the protection theory can be increased if the postulated positioning persists across several troops despite significant opportunities for variation, and if progression order is shown to be linked to biological phenomena such as sex differences in physical maturation. Data from 73 individually identified, free-ranging juveniles of both sexes were compared with previous findings. Small juveniles of several troops were more centrally located than large juveniles. Large juveniles males were more toward the front than were large juvenile females. As male walking infants and juveniles aged, a change in positioning (i.e., location) occurred: males were located increasingly toward the front of progressions. Comparable data from females suggest that the adult female pattern had begun to form among large juveniles. Data are consistent with an ultimate protection theory.     

Ectopic splenic nodules in the olive baboon (Papio cynocephalus anubis)

Post-mortem evaluation of a female sub-adult olive baboon (Papio cynocephalus anubis) revealed a case of ectopic spleen anomaly. Three spherical masses characterized the spleen anomaly. The splenic nodules were located on the left upper quadrant of the stomach, at the distal end of the pancreas. The anterior nodule measures 1.2 cm, the middle nodule 1.9 cm and the posterior nodule 1.3 cm in diameter. Normal spleen was not observed in this case. All the three ectopic splenic nodules showed normal histological architecture. A case of ectopic splenic nodules in baboon is important in that the spleen malformation can readily be mistaken for a pathological process.     

A 4-year summary of the nonsurgical recovery of baboon embryos: A report on 498 eggs

A nonsurgical embryo recovery procedure, developed to allow the economical acquisition of cleavage stage baboon embryos, has been successfully used for 4 years. With this technique, 498 eggs have been recovered from 979 uterine flushes (50.9%) on 71 baboons. Of 467 eggs recovered from mated baboons, 290 (62.1%) were fertilized. Papio anubis females provided a higher percentage of fertilized eggs (75.3%) than did Papio hamadryas (47.8%) or Papio cynocephalus (44.3%) females following exposure to males during estrus, although sexual preference may be responsible for the reduced fertilization rate in the P. cynocephalus females. Recovery rates from individual baboons ranged from 0% (n = 11) to between 66% and 93% for ten baboons from each of which 12–33 eggs have been recovered. Fertilized eggs were at the two-cell (n = 23) to blastocyst (n = 53) stage at recovery 1–6 days postdeturgescence (PD) of the sex skin, with morulae (n = 84) being the most frequent cell stage recovered (30%). The optimum time for performing the procedure was the third day PD, when 113 (40%) embryos were recovered. The abilities of baboons to become pregnant and to provide fertilized embryos were significantly related (P < 0.005), allowing the embryo recovery technique to be used as a screening procedure for evaluating baboon fertility.     

Carbonic anhydrase isoenzymes in nine troops of Kenya baboons, Papio cynocephalus (Linnaeus 1766)

The distributions of alleles at the carbonic anhydrase I (CA I = CA B) and carbonic anhydrase II (CA II = CA C) loci in nine troops of Papio cynocephalus were determined. Two alleles were found at the CA I locus, and three at the CA II locus; the frequencies were: CA I^a = 0.856; CA I^b = 0.144; CA II^a = 0.784; CA II^b = 0.209; CA II^c = 0.007. Results of tests for Hardy-Weinberg equilibrium, homogeneity tests, and calculations of migration rates were used in support of the interpretation that migration and genetic drift may affect the distribution of alleles at the CA I locus and that selection is the process responsible for the distribution of alleles at the CA II locus.     

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.     

Analysis of infant handling and the effects of female rank among Tana River adult female yellow baboons (Papio cynocephalus cynocephalus) using permutation/randomization tests.

Infant handling has been documented in numerous species. Among cercopithecines, interaction motivations are reported to range from aunting to kidnapping; these interactions are often distressful for both mother and infant. Here we examine handling by adult female yellow baboons (Papio cynocephalus cynocephalus) at the Tana River National Primate Reserve, Kenya, using a relatively new, computer-intensive statistical approach of permutation/randomization tests to deal with repeated measures effects and a skewed sample. We hypothesized 1) a tendency for handlers to handle the infants of females ranked similarly or lower than themselves, and 2) more successful infant handling by higher-ranked females, particularly with very young infants. We collected focal data on 23 females (11 mother-infant pairs) over an 11-mo period, with a total of 303 attempted and/or successful "handles" utilized in the permutation analyses. The general patterns apparent in the data seemed to support our hypotheses. However, the permutation tests showed that while females are somewhat more likely to attempt to handle the infants of females ranked "same or lower" than themselves, lower-ranked females are able to prevent more than three-fourths of the attempted interactions, and there is no statistically significant trend for females to successfully handle these infants. Further refinement of the analyses showed no significant tendencies for females to handle those infants ranked "lower" or "immediately lower" than themselves, casting doubt on the significant finding for "same or lower" attempts. Further, there was no significant effect for higher-ranked females to successfully handle an infant during its first month. Thus, rank does not seem to offer any privileges in terms of handling an infant in this population. We believe the permutation tests are an effective way to analyze repeated measures data and offer a more sensitive analysis tool for determining true significance.     

Insect and meat eating among infant and adult baboons (Papio cynocephalus) of Mikumi National Park, Tanzania

It has been suggested that baboon predation upon vertebrates may tend to peak in the dry season because insect food is then less available, and that males obtain animal nutrients primarily from vertebrates whereas other troop members obtain them primarily from invertebrates. The development of meat and insect eating by 22 male and 24 female infants studied for 25 months was compared with that of 18 male and 46 female adults studied for 37 months. Systematic sampling allowed quantitative comparisons between meat and insect eating, infants and adults, and males and females. Infants ate no meat, but their insect eating began early and increased steadily during the first year of life. In comparison with insect foods, meat was a minor ingredient of the adult's diet. Insect eating occurred less during dry than during rainy months, but meat eating was spread across the year. Reliable sex differences in insect eating did not occur. The findings were related to theories offered to explain the attractiveness of animal foods to primates and to the suggestion that a sex difference in predatory inclinations of hominid ancestors may have been a preadaptation underlying the eventual emergence of male hunting and female gathering.     

The brief survival of free-ranging baboon infants (Papio cynocephalus) after separation from their mothers

The importance of mother — infant attachment in free-ranging primates is illustrated by events culminating in the deaths of two baboon infants a few days after losing their mothers. These two cases are contrasted with those of a severely injured infant, not separated from its mother, which lived, and an animal which lost and refound its troop. Protective behavior of adult males is described. In captivity, separation sometimes produces infant depression; in nature, such depression may be fatal.     

Brief report: Body water estimates in normally grown baboon neonates

Water contents of various body water compartments were estimated within nine hours of birth in 11 preterm and eight term baboon (Papio cynocephalus neonates. Estimated water contents of all body compartments (in ml) increased linearly with birthweight (r = 0.52 to 0.90, P ≦ 0.007) and with gestational age (r = 0.46–0.94, P ≤ 0.05). When body water estimates were expressed in proportion to bodyweight (in ml/kg), preterm neonates had significantly larger mean antipyrine space and intracellular water than their term peers. Mean corrected bromide space, interstitial water, plasma volume, blood volume, and red cell volume were similar in preterm and term neonates. Although there are minor differences in body water contents and distribution between baboon and human neonates, baboon data are sufficiently similar to human data to justify using the baboon fetus and neonate as a model for investigations of human development.     

Crossing the Red Sea: phylogeography of the hamadryas baboon, Papio hamadryas hamadryas

The hamadryas baboon (Papio hamadryas hamadryas) is found both in East Africa and western Arabia and is the only free-ranging nonhuman primate in Arabia. It has been hypothesized that hamadryas baboons colonized Arabia in the recent past and were possibly even transported there by humans. We investigated the phylogeography of hamadryas baboons by sequencing a portion of the control region of mtDNA in 107 baboons from four Saudi Arabian populations and combing these data with published data from Eritrean (African) P. h. hamadryas. Analysis grouped sequences into three distinct clades, with clade 1 found only in Arabia, clade 3 found only in Africa, but clade 2 found in both Arabian and African P. h. hamadryas and also in the olive baboon, P. h. anubis. Patterns of variation within Arabia are neither compatible with the recent colonization of Arabia, implying that baboons were not transported there by humans, nor with a northerly route of colonization of Arabia. We propose that hamadryas baboons reached Arabia via land bridges that have formed periodically during glacial maxima at the straits of Bab el Mandab in the southern Red Sea. We suggest that the genetic differentiation of Arabian from African populations suggests that Arabian populations have a higher conservation status than recognized previously.     

Distribution and Habitat Associations of Baboons (Papio hamadryas) in Central Eritrea

At least three diurnal primate taxa are still present in Eritrea, NE Africa: hamadryas baboons (Papio hamadryas hamadryas), olive baboons (Papio h. anubis) and grivet monkeys (Chlorocebus aethiops aethiops). However, information on status and distribution of primates and their habitats in Eritrea is outdated and incomplete. We conducted a primate survey, focussing on hamadryas baboons, to obtain data which will be integrated in a national wildlife management and conservation plan in Eritrea. We obtained information about the geographical distribution and abundance of baboons, their altitudinal range, habitat quality of their home-ranges, aggregation sizes at sleeping cliffs and predator presence. We described habitat quality via the Normalized Difference Vegetation Index (NDVI), a vegetation classification of Landsat MSS satellite data. Hamadryas and olive baboons are still present in Eritrea in ample numbers. Their geographical distributions in 1997 and 1998 did not deviate significantly from their historical distributions. An estimated 15,000 Papio hamadryas hamadryas lived in the 25,000-km² area of survey (0.58 baboons/km²). Population densities of hamadryas baboons in many parts of the survey area are higher than at Kummer's (1968) study site in Ethiopia. Hamadryas baboons live at all altitudes in four of five ecogeographical zones of Eritrea. Olive baboons replaced them in the western lowlands. Both baboon taxa tend to select better quality habitats, characterized by a higher normalized difference vegetation index (NDVI) than the average for the respective ecogeographical zones. Hamadryas baboons show a greater ecological plasticity than olive baboons, which are confined to riverbeds with extended gallery forest. By the end of 1999, a hybrid zone could not be confirmed.