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Adult Chimpanzees (adult + chimpanzee)
Selected AbstractsDynamic in-hand movements in adult and young juvenile chimpanzees (Pan troglodytes)AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 3 2009Jessica Crast Abstract Descriptions of manual function in nonhuman primates have largely focused on static precision and power grasping (as first defined by Napier,1956), while identification and description of dynamic manual function are rare and incomplete. Here, we describe several forms of in-hand movements used by chimpanzees (Pan troglodytes) when manipulating small objects. In-hand movements are defined as the movement of an object within one hand via manipulation of the digits. We presented adult and young juvenile chimpanzees (ages 5,29 years) with a task that required inserting small objects through correspondingly shaped cutouts in a transparent Plexiglas panel. While attempting to insert the objects through the cutouts, the subjects used at least two forms of in-hand movements to change their grip on the object for more precise alignment. We describe in detail the in-hand movements they used and the variability observed in form and execution among the subjects. In general, the adult subjects used in-hand movements more frequently and used a wider variety of forms than did the young juvenile subjects, suggesting that in-hand movements are in the process of fine-tuning around the age of 5 years in chimpanzees. The dexterity exhibited by the adults, however, shows that the neuromuscular and morphological requirements for relatively complex digital manipulation are present in the adult chimpanzee. Am J Phys Antropol, 2009. © 2008 Wiley-Liss, Inc. [source] Gravity bias in young and adult chimpanzees (Pan troglodytes): tests with a modified opaque-tubes taskDEVELOPMENTAL SCIENCE, Issue 3 2007Masaki Tomonaga Young human children at around 2 years of age fail to predict the correct location of an object when it is dropped from the top of an S-shape opaque tube. They search in the location just below the releasing point (Hood, 1995). This type of error, called a ,gravity bias', has recently been reported in dogs and monkeys. In the present study, we investigated whether young and adult chimpanzees also show such a gravity bias in a modified version of the original opaque-tube task. The original task by Hood and colleagues required the subject to search in a location after the object had fallen, while in the task reported here, subjects were required to predict the location before the object was dropped. Thus the present procedure does not involve explicit invisible displacement operations, one of the important components of the original procedure. In Experiment 1 both young (1.5,2.5-year-old) and adult chimpanzees predicted the location of falling food items below the releasing point even when crossed tubes were used. These gravity errors remained after the extensive experience of using the tubes themselves. Experiment 2 further tested adult and 4-year-old chimpanzees under the set-up in which the straight and crossed tubes were simultaneously presented. The results were the same as those in the previous test, suggesting that developmental changes and learning effect do not affect the gravity bias in chimpanzees. [source] Components of Relationship Quality in ChimpanzeesETHOLOGY, Issue 9 2008Orlaith N. Fraser A novel approach to studying social relationships in captive adult chimpanzees (Pan troglodytes) was taken by using principal components analysis (PCA) to extract three key components of relationship quality from nine behavioural variables. Based on the loadings of the behavioural variables, the components appeared to match previously hypothesized critical aspects of social relationships and were therefore labelled Value, Compatibility and Security. The effects of kinship, sex combination, age difference and time spent together on each of the relationship quality components were analysed. As expected, kin were found to have more valuable, compatible and secure relationships than non-kin. Female,female dyads were found to be more compatible than male,male or mixed-sex dyads, whereas the latter were found to be most secure. Partners of a similar age were found to have more secure and more valuable relationships than those with a larger age gap. Individuals that were together in the group for longer were more valuable and more compatible, but their relationships were found to be less secure than individuals that were together in the group for a shorter time. Although some of the results may be unexpected based on chimpanzee socio-ecology, they fit well overall with the history and social dynamics of the study group. The methods used confer a significant advantage in producing quantitative composite measures of each component of relationship quality, obtained in an objective manner. These findings therefore promote the use of such measures in future studies requiring an assessment of the qualities of dyadic social relationships. [source] Temperature's influence on the activity budget, terrestriality, and sun exposure of chimpanzees in the Budongo Forest, UgandaAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 2 2009Valerie P. Kosheleff Abstract Chimpanzee (Pan troglodytes schweinfurthii) activity budget, terrestriality, and sun exposure were found to be influenced by the immediate environmental temperature. Thirty adult chimpanzees in the Budongo Forest, Uganda, were observed for 247 h. Temperatures in the shade and sun, sky cover, sun exposure, activity, and terrestriality were recorded at 5-min intervals at <15 m from the center of the party. Terrestriality frequency was 26.5% for females and 41.5% for males. Terrestriality and resting both show a significant positive correlation with temperature in the sun. Controlling for seven potential confounding factors, temperature in the sun remained the strongest predictor of terrestriality. The difference between temperatures in the sun and shade had a significant effect on chimpanzee sun exposure frequency. Time spent continuously in the sun was negatively correlated with temperature, beginning to decrease around 30°C, and markedly decreasing around 40°C. A concurrent experiment determined that dark pelage (lacking physiological coping mechanisms) exposed to the same solar regime can easily reach 60°C within minutes. This study indicates that both temperature in the sun and sun exposure play a role in influencing chimpanzee activity behavior, and specifically suggests that chimpanzees thermoregulate behaviorally both by moving to the ground and by decreasing their activity level. These results, in the context of deforestation and increasing global temperatures, have physiological and conservation implications for wild chimpanzees. Am J Phys Anthropol, 2009. © 2008 Wiley-Liss, Inc. [source] Reconciliation, consolation and postconflict behavioral specificity in chimpanzeesAMERICAN JOURNAL OF PRIMATOLOGY, Issue 12 2008Orlaith N. Fraser Abstract Conflicts of interest arise regularly in the lives of all group-living animals and may escalate into aggressive conflicts. The costs of aggressive escalation can be reduced through peaceful postconflict interactions. This study investigated the postconflict behavior of 22 adult chimpanzees at Chester Zoo. The occurrence of reconciliation, i.e. the postconflict affiliative reunion between conflict opponents, and consolation, i.e. a postconflict affiliative interaction directed from a third party to the recipient of aggression, were demonstrated. Consolation was more likely to occur in the absence of reconciliation than after reconciliation, and reconciliation was more likely to occur in the absence of consolation than after consolation, supporting the hypothesis that consolation acts as a substitute for reconciliation when the latter fails to occur. Evidence for behavioral specificity, i.e. context-specific use of certain behaviors, was found for both reconciliation and consolation, which, along with high conciliatory tendencies, suggests an explicit style of postconflict behavior in the study subjects. Am. J. Primatol. 70:1114,1123, 2008. © 2008 Wiley-Liss, Inc. [source] Effects of aging on hematology and serum clinical chemistry in chimpanzees (Pan troglodytes)AMERICAN JOURNAL OF PRIMATOLOGY, Issue 4 2008Elaine N. Videan Abstract A number of age-related changes in physiological functions have been identified in macaques and humans. However, few studies have examined physiological aging in chimpanzees, despite the increasing age of the chimpanzee population. We documented age-related changes in seven hematology and 17 clinical chemistry parameters in 49 adult chimpanzees (17 males, 32 females) as a comparative viewpoint with human and macaque aging. Longitudinal data were analyzed using weighted linear and quadratic mixed effects regression models. Male chimpanzees exhibited a significant age-related increase in anemia risk, based on significant decreases in hemoglobin (F1,49=12.45, P=0.0009) and hematocrit (F1,49=15.42, P=0.0003). Both sexes exhibited significant age-related decreases in both kidney and liver function. Decreases in kidney function were noted by significant increases in blood urea nitrogen (F1,45=3.92, P=0.036) and creatinine (F1,50=5.63, P=0.022) as well as changes in electrolyte (i.e., sodium, potassium, phosphorous, chloride) balance. Declining liver function was based on significant increases in globulin (F1,46=32.34, P<0.0001) and decreases in albumin (F1,48=23.42, P<0.0001). These changes were most evident beginning at 25,30 years of age in males and 30,35 years of age in females. We recommend amending chimpanzee age classes to categorize males over 25 years and females over 30 years as aged. Am. J. Primatol. 70:327,338, 2008. © 2007 Wiley-Liss, Inc. [source] | ||||||||||