Anthony M. Coelho

Kin recognition by paternal half-siblings in captive Papio cynocephalus

Our objective in this study was to evaluate whether a group of paternally related, subadult baboons (Papio cynocephalus) would preferentially interact with kin or nonkin when they had been raised apart from kin other than their mothers. Subjects and their mothers were removed from the breeding group and placed in alternate housing within 24 h after birth to ensure that the subjects would not have a social history with either their sire or their half‐siblings. At 90 days of age, the 23 subjects were separated from their mothers and assigned to a peer–peer social group. Behavioral performance was measured using focal animal sampling techniques and 12 molecular behavioral criteria. Analyses of the data indicate that in dyadic interactions kin did not interact more frequently than nonkin in performance of affiliative, sociosexual, and agonistic behaviors. The hypothesis that baboons recognize kin in the absence of maternal associations was not supported by the data; moreover, we suggest that social learning and social history are the most likely mechanisms for kin recognition. Am. J. Primatol. 43:147–157, 1997.

Sexual dimorphism in the activity of olive baboons (Papio cynocephalus anubis) housed in monosexual groups

In this study, responses to the formation of social groups were compared between adult male and female Papio cynocephalus anubis. Quantitative behavioral data based on systematic focal animal sampling were used to test the hypothesis that adult male and female olive baboons are similar in their behavioral response to (1) the formation of monosexual social groups and (2) the simultaneous reduction of social unit and habitat size. Males and females differed (ttest, p <0.05) in performance of sexual, tension, and stereotypy behavior during large group formations. During small group formations, males and females differed in play, subordinate, locomotion, manipulation, sexual, tension, and stereotypy behavior. Our observations, clearly indicate that in captivity, under conditions of identical housing, social structure, and social unit history, males and females differ in their behavior performance. Our data suggest that some socioenvironmental conditions, such as the lack of heterosexual grouping, may exaggerate those differences.

Early rearing experiences and the performance of affinitive and approach behavior in infant and juvenile baboons

We tested the hypothesis that subtle, short-term (birth to 3 months) differences in rearing experiences (peer-peer vs. mother-peer) produce measurable differences in the development and performance of four affinitive and four approach behaviors in late infancy (12 months of age) and in the late juvenile period (42 months of age). Data on 87 monkeys (45 males and 42 females) were obtained by a series of approximately 2,100 focal animal sampling sessions. Significant effects of rearing were found in two affinitive behaviors (Allogroom andHold) with mother-peer reared subjects having a higher mean rate of performance. There were no significant main effects or interactions among any of the approach behaviors. Several suggestions are proposed to account for the resistance of six behaviors (Muzzle-muzzle, Touch, Ear flatten, Follow, Lip smack andSocial approach) to the effects of the experimental procedures: (1) these behaviors may reflect genetically mediated behavioral characteristics of the species that are not modified by environmental conditions; (2) environmental conditions used in the study may have been too subtle and consequently insufficient to produce an effect on relatively resistant behaviors; or (3) effects of the early rearing experience on these behaviors may be observable only during adolescence or adulthood when the proper performance of these behaviors is more crucial to social success, social integration and reproduction.

The effects of sexual status on threat, attack and subordinate behaviors of papio monkeys.

Performance and reception of threat, attack, and subordinate behaviors at different phases of the perineal cycle in 24 female papio monkeys (superspecies Papio cynocephalus)was compared. The subjects ranged in age from 36 to 42 months at the inception of the study and were observed over a 2-year period. Females performed significantly fewer threat and attack behaviors during the swollen phase of the perineal cycle and showed no significant differences in the reception of the three behavioral measures. The reduction in the performance of aggression that occurs during the swollen phase of the perineal cycle reflects a shift in the focus of interactions during consortship to a single male.

Neonatal nutrition and longitudinal growth in baboons: Adiposity measured by skinfold thickness

This paper reports the results of a 5 year longitudinal experiment that (1) examined growth in adiposity of a group of 48 clinically normal olive savannah baboons (Papio cynocephalus anubis) who were randomly assigned at birth to one of three diet treatments that differed, during the first 16 weeks, in the amount of nutrients they provided; (2) tested the hypothesis that different amounts of food availability during the neonatal period (birth to 16 weeks) had a significant effect on growth and development of adiposity in the subsequent infant, juvenile, and adolescent periods; and (3) evaluated the extent to which underfed (LC) and overfed (HC) subjects were capable of growth canalization. Each diet contained different caloric densities but the same proportion of fat (34%), carbohydrate (55%), and protein (11%). All animals were fed the same volume of formula; however, HC subject were fed 40% more calories than MC subjects, who were fed 40% more calories than the LC subjects. Growth and development of adiposity were assessed by measuring neck, triceps, subscapular, and suprailiac skinfolds weekly from birth to 16 weeks and at 13 week intervals from 26 to 260 weeks of age. We found that during the first 16 weeks of the experiments, baboon growth was strongly influenced by food shortages but not by excesses; however, when the dietary treatment ceased, growth appeared to be strongly regulated by a genetic component (developmental canalization) and tended to return to a more normal growth pattern within a 26 week time frame. Males and females exhibited differences in adipose development in that males did not exhibit residual treatment effects while females tended to retain the effects of neonatal dietary treatments through early adolescence.

Is Lipsmacking an Indicator of Social Status in Baboons

Lipsmacking is performed by many Old World monkey species, and some studies of baboons and macaques suggest that lipsmacking may be associated with social status. We studied 60 adult anubis baboons (Papio cynocephalus anubis) for 18 months, measured social status and the rate of lipsmacking, and used these data to test the hypothesis that lipsmacking is related to social status. Our results indicate that social status and lipsmacking were not significantly correlated for either males or females. Analysis of lipsmacking in relation to social class (high vs. low) showed no significant difference between status classes for either sex. Lipsmacking was, however, found to be positively associated with affinitive behaviors. These results suggest that baboon lipsmacking provides positive social communication independently of social status.

Training adaptations of baboons to light and moderate treadmill exercise

We evaluated training adaptations by 18 baboons (Papio cynocephalus anubis) to low and moderate quadrupedal walking exercise on a motorized treadmill. Moderate training produced 47% increases in lactate threshold, 63% increases in muscle citrate synthetase activity, increases in percentage of Type IIc muscle fibers, and reduced plasma insulin concentrations. Low training produced only reduced plasma insulin concentrations. Our results indicate that the baboon response to exercise training was similar to that of Homo sapiens, and dependent on exercise intensity.

Studies on the Effects of 60-Hz Electric and Magnetic Fields on Neuroendocrine Circadian Rhythmicity in Nonhuman Primates

Wilson et al. (1981, 1983, 1986) demonstrated that exposure of rats to electric fields for 3 weeks both reduces, by about 50%, the amplitude of the nocturnal peak in melatonin production by the pineal gland and delays, by about 2 hours, the time of peak melatonin production. Semm (1983), Welker et al. (1983), and Olcese and Reuss (1986) have demonstrated magnetic field effects on pineal melatonin synthesis in rodents.