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Vervet Monkeys (vervet + monkey)
Selected AbstractsRed-tail monkey groups in forest patches outside the protected area system in the ,Kampala area'AFRICAN JOURNAL OF ECOLOGY, Issue 2004D. Baranga Abstract This study was conducted in the ,Kampala area', a forest-savanna-agricultural mosaic, and was aimed at investigating the ecology and survival of the red-tail monkey, Cercopithecus ascanius schmidti in fragmented forest patches outside the protected area system. The relationship between habitat variables and red-tail monkeys' distribution and other demographic factors were investigated. The average group size for red-tail monkeys in the forest patches was 11.9, while that in Mpanga Forest Reserve it was 23.2. Most of the red-tail monkey groups had breeding females but there were small populations with no breeding females. The number of breeding females and young varied in different forest patches with the breeding sex ratio ranging from 0 to 1:3. The residential status of red-tails in the patches was partly influenced by the presence of the vervet monkey and the intensity of human activities in the vicinity. [source] ,Morphing monkeys', or ,geo-eco-morphology of the vervet monkey'JOURNAL OF BIOGEOGRAPHY, Issue 10 2007Alexander Harcourt No abstract is available for this article. [source] Disruption of self-organized actions in monkeys with progressive MPTP-induced parkinsonism.EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 2 2004Abstract Parkinson's disease (PD) is characterized by motor symptoms, usually accompanied by cognitive deficits. The question addressed in this study is whether complexity of routine actions can exacerbate parkinsonian disorders that are often considered to be motor symptoms. To examine this question, we trained four vervet monkeys (Cercopithecus aethiops) to perform three multiple-choice retrieval tasks. In order of ascending complexity, rewards were freely available (task 1), covered with transparent sliding plaques (task 2), and covered with opaque sliding plaques cued by symbols (task 3). Thus, from task 1 to task 2 we added a motor difficulty , the recall of context-adapted movement; and from task 2 to task 3 we added a cognitive difficulty: the recall of symbol,reward associations. The more complex the task, the longer it took to learn, but after extensive training the performance was stable in all tasks, with similar retrieval durations. The monkeys then received systemic 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) injections (0.3,0.4 mg/kg) every 4,7 days, until the first motor symptoms appeared. In the course of MPTP intoxication, the behavioural performance declined while the motor symptoms were absent or mild , the retrieval duration increased, and non-initiated choices and hesitations between choices became frequent. Interestingly, this decline was in proportion to task complexity, and was particularly pronounced with the cognitive difficulty. Furthermore, freezing appeared only with the cognitive difficulty. We therefore suggest that everyday cognitive difficulties may exacerbate hypokinesia (lack of initiation, abnormal slowness) and executive disorders (hesitations, freezing) in the early stages of human PD. [source] Disruption of self-organized actions in monkeys with progressive MPTP-induced parkinsonism: II.EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 2 2004Effects of reward preference Abstract The motor and cognitive symptoms of Parkinson's disease (PD) are well documented, but little is known about the functionality of motivational processes mediated by the limbic circuits of basal ganglia. The aim of this study was to test the ability of motivational processes to direct and to urge behaviour, in four vervet monkeys (Cercopithecus aethiops) progressively intoxicated with systemic 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) injections (0.3,0.4 mg/kg every 4,7 days). In the food preference task, the monkeys had to retrieve two types of directly visible food, simultaneously available in the wells of a reward board. At all stages of MPTP-induced parkinsonism, the monkeys continued to take their favourite food first. In the symbol discrimination task, the wells were covered with sliding plaques cued by symbols indicating the absence or presence of a reward, and the different types of food were blocked in separate sessions. Monkeys with mild or moderate parkinsonism made fewer attempts and took longer to retrieve non-preferred compared with preferred rewards. These results indicate that motivational processes are still able to direct (food preference task) and to urge (symbol discrimination task) behaviour in MPTP-lesioned monkeys. Such a functional preservation may be related to the relatively spared dopaminergic innervation of the limbic circuits that we found in our monkeys, in agreement with the literature on humans. Furthermore, the frequency of executive disorders (such as hesitations and freezing) appeared to be much lower with the preferred rewards. Thus, the preserved motivational processes may help to overcome executive dysfunction in the early stages of human PD. [source] Secondary sexual coloration and CSF 5-HIAA are correlated in vervet monkeys (Cercopithecus aethiops sabaeus)JOURNAL OF MEDICAL PRIMATOLOGY, Issue 6 2007M.S. Gerald Abstract Background, Identifying indirect markers of the physiology or neuroendocrinology of a primate can provide a powerful tool to scientists. Anecdotal descriptions and recent experimental evidence suggests that the colorful sexual skin in adult male vervet monkeys (Cercopithecus aethiops sabaeus) might be sensitive to social changes, including dominance relationships, which could be related to serotonergic activity. The present study examined whether individual differences in scrotal coloration were related to cisternal cerebrospinal fluid concentrations of 5-hydroxyindoleacetic acid (CSF 5-HIAA) in a captive population of vervet monkeys. Results, Darkly colored males had relatively higher CSF 5-HIAA concentrations than paler males, and scrotal color hue was also related CSF 5-HIAA concentrations. Conclusions, These preliminary data are compatible with the hypothesis that scrotal coloration serves as an indirect marker of serotonergic activity. These findings suggest that color assessments might be useful to consider for study design, as well as for animal welfare and captive management. [source] Endocrine mechanisms of primate life history trade-offs: Growth and reproductive maturation in vervet monkeysAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 6 2009Patricia L. Whitten Life history theory predicts that the timing of maturation will result from a trade-off between growth and the age of first reproduction. This trade-off and its mechanisms of action are still poorly understood in many species and have not been well studied at the individual level. This study examined hypothesized trade-offs between growth and reproductive maturation in wild populations of vervet monkeys (Cercopithecus aethiops) from Kenya, East Africa. Individuals were sampled from four populations in widely separated sites differing in temperature, altitude, and rainfall. Biological samples and morphometric measures were collected from 50 adult males, 83 adult females, and 225 juveniles. Gonadal steroids and leptin levels were analyzed by radioimmunoassay of sera from 136 juvenile males and 90 juvenile females. Cross-sectional profiles of morphometric and endocrine data were used to assess the onset and cessation of growth in relation to sexual maturation. Gonadal steroids were used to assess sexual maturation and breeding onset. Leptin was used as an index of nutritional state. Estimates of mortality were derived from population age-structure. Across populations, higher resource productivity and nutrient status were associated with more rapid growth. Shorter growth duration was associated with earlier reproductive onset. These findings provide support for models of trade-offs between the timing of growth completion and reproductive onset, but they are contradicted by the evidence that reproduction precedes the cessation of growth in these populations. The biphasic actions of estradiol provide an alternative model and mechanism for the growth-reproduction trade-off. Am. J. Hum. Biol., 2009. © 2009 Wiley-Liss, Inc. [source] Comparison of responses to alarm calls by patas (Erythrocebus patas) and vervet (Cercopithecus aethiops) monkeys in relation to habitat structureAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 1 2002Karin L. Enstam Abstract We studied responses to alarm calls of sympatric patas (Erythrocebus patas) and vervet (Cercopithecus aethiops) monkeys in relation to habitat structure, with the intention of understanding the relationship between the environment and predator avoidance. Patas and vervet monkeys are phylogenetically closely related and overlap in body size. However, while patas monkeys are restricted to nonriverine habitats at our study site, vervets use both nonriverine and riverine habitats, allowing us to "vary" habitat structure while controlling for effects of group size, composition, and phylogeny. Patas monkeys in the nonriverine habitat responded to mammalian predator alarm calls with a greater variety of responses than did vervets in the riverine habitat, but not when compared with vervets in the nonriverine habitat. Ecological measurements confirm subjective assessments that trees in the riverine habitat are significantly taller and occur at lower densities than trees in the nonriverine habitat. Despite the lower density of trees in the riverine habitat, locomotor behavior of focal animals indicates that canopy cover is significantly greater in the riverine than the nonriverine habitat. Differences in responses to alarm calls by the same groups of vervets in different habitat types, and convergence of vervets with patas in the same habitat type, suggest that habitat type can be a significant source of variation in antipredator behavior of primates. Am J Phys Anthropol 119:3,14, 2002. © 2002 Wiley-Liss, Inc. [source] Changes in ranging and agonistic behavior of vervet monkeys (Cercopithecus aethiops) after predator-induced group fusionAMERICAN JOURNAL OF PRIMATOLOGY, Issue 7 2010Karin Enstam Jaffe Abstract Socio-ecological theory predicts that group fusion in female-philopatric primate species will be rare because females experience increased costs by associating with non-relatives. Indeed, fusion has been reported only 14 times in only 4 female-philopatric cercopithecines despite many years of observation. Here, we describe changes in ranging and agonistic behavior of vervet monkeys (Cercopithecus aethiops) after the fusion of two groups, the sole group fusion during 11 years of observation, induced by a brief but intense period of apparent leopard predation. Before fusion, both groups made few incursions into the other group's territory and spent most of the time in their own territories. After the fusion, the amalgamated group shifted its activities and used both territories in similar proportion. Rates of female agonism increased after fusion, particularly in the 2 weeks following fusion, and the small group females assumed the lowest ranks in the female dominance hierarchy. Rates of agonism returned to prefusion rates a month later. Although rates of high-intensity interactions (i.e., chases) did not increase after fusion, small group females were more likely to be the recipients of, and lose, agonistic interactions than large group females; a small group female and her infant were attacked and wounded by a coalition of large group females shortly after the fusion. The observations presented here reveal that the circumstances surrounding group fusions are more variable than previously realized, but are still in accordance with expectations from socio-ecological theory that predation can favor the formation of larger groups. In this case, under threat of severe predation, individuals may have surrendered group autonomy for the greater security of larger numbers. Am. J. Primatol. 72:634,644, 2010. © 2010 Wiley-Liss, Inc. [source] High-fiber diet promotes weight loss and affects maternal behavior in vervet monkeysAMERICAN JOURNAL OF PRIMATOLOGY, Issue 3 2010Lynn A. Fairbanks Abstract The dramatic increase in obesity in western societies has shifted the emphasis in nutrition research from the problems of undernutrition to the adverse consequences of being overweight. As with humans, Old World monkeys are at increased risk for type II diabetes and other chronic diseases when they gain excessive weight. To prevent overweight and obesity, promote animal health, and provide a more natural level of fiber in the diet, the standard commercial monkey chow diet at a vervet monkey breeding colony was changed to a higher fiber formulation in 2004. The new diet was also higher in protein and lower in carbohydrate and energy density than the standard diet. Because maternal behavior is known to be sensitive to differences in resource availability, data on weight and mother,infant interactions for 147 mothers with 279 infants born from 2000 through 2006 were assessed for effects of the diet change. The results showed that, even though food was provided ad libitum, the mean body weight of breeding females was 10% lower after the transition to the high-fiber diet. Behaviorally, mothers on the high-fiber diet were significantly more rejecting to their infants, and their infants had to play a greater role in maintaining ventral contact in the first few months of their lives. The effects of the diet change on maternal rejection were significantly related to the mother's body weight, with lower-weight mothers scoring higher in maternal rejection. These results demonstrate that maternal behavior is responsive to changes in maternal condition, and that beneficial changes in the diet may have unintended consequences on behavior. Am. J. Primatol. 72:234,241, 2010. © 2009 Wiley-Liss, Inc. [source] After the fire: benefits of reduced ground cover for vervet monkeys (Cercopithecus aethiops)AMERICAN JOURNAL OF PRIMATOLOGY, Issue 3 2009Karin Enstam Jaffe Abstract Here we describe changes in ranging behavior and other activities of vervet monkeys (Cercopithecus aethiops) after a wildfire eliminated grass cover in a large area near the study group's home range. Soon after the fire, the vervets ranged farther away from tall trees that provide refuge from mammalian predators, and moved into the burned area where they had never been observed to go before the fire occurred. Visibility at vervet eye-level was 10 times farther in the burned area than in unburned areas. They traveled faster, and adult females spent more time feeding and less time scanning bipedally in the burned area than in the unburned area. The burned area's greater visibility may have lowered the animals' perceived risk of predation there, and may have provided them with an unusual opportunity to eat acacia ants. Am. J. Primatol. 71:252,260, 2009. © 2008 Wiley-Liss, Inc. [source] | ||||||||||