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From January 2006 to January 2008, we collected 1,045 fecal samples from 90 individually-recognized, free-ranging, eastern chimpanzees (Pan troglodytes schweinfurthii) inhabiting Gombe National Park, Tanzania to determine how patterns of parasitism are affected by demographic and ecological covariates. Seventeen parasite species were recovered, including eight nematodes (Oesophagostomum sp., Necator sp., Probstmayria gombensis, Strongyloides fulleborni, Ascaris sp., Trichuris sp., Abbreviata caucasica, and an unidentified strongyle), 1 cestode (Bertiella sp.), 1 trematode (Dicrocoeliidae), and 7 protozoa (Entamoeba coli, Entamoeba histolytica/dispar, Iodamoeba butschlii, Troglodytella abrassarti, Troglocorys cava, Balantidium coli, and an unidentified protozoa). Significant differences were observed in interannual infection prevalence and parasite richness between 2006 and 2007. Intercommunity comparisons demonstrated higher prevalence of parasites for the Mitumba compared with Kasekela chimpanzee community. Prevalence of several parasites was strongly correlated with monthly rainfall patterns for both 2006 and 2007. Subadult chimpanzees had lower prevalence for most parasite species compared with adults in both years and also yielded a lower average parasite species richness. No significant differences were observed between males and females in prevalence in 2006. However, in 2007 the prevalence of S. fulleborni and I. butschlii were higher in males than in females. Parasite prevalence and richness were substantially higher in this multiyear study compared with previous short-term studies of the gastrointestinal parasites of Gombe chimpanzees. This coupled with the significant interannual and interseasonal variation, demonstrated in this study, emphasizes the importance of multiyear monitoring with adequate sample size to effectively determine patterns of parasitism in wild primate populations. Am J Phys Anthropol 143:534-544, 2010. [c] 2010 Wiley-Liss, Inc. KEY WORDS apes; gastrointestinal parasites; health; noninvasive analyses; zoonoses DOI 10.1002/ajpa.21348

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.anbehav.2009.11.003 Byline: Fumihiro Kano (a)(b), Masaki Tomonaga (a) Abstract: How do chimpanzees, Pan troglodytes, the species with the closest evolutionary connection to humans, view faces? This study is the first to use the eye-tracking method to perform direct comparisons between humans and chimpanzees with regard to face scanning. Members of both species viewed the same sets of photographs representing conspecific and nonconspecific faces under the same experimental conditions. Chimpanzees and humans showed systematic and similar patterns of face scanning, including intensely viewing main facial features (i.e. eyes, nose and mouth) and inspecting the eyes and mouth, in that order. However, several differences between the species were also evident. For example, humans were more likely to show sequential refixations on the eye regions than were chimpanzees, whereas chimpanzees were more likely to engage in quick, vertical scanning over the eyes and mouth. Such species similarities and differences were consistent across conspecific and nonconspecific faces and were thus independent of the external morphologies of species-specific faces. Furthermore, when presented with facial expressions, chimpanzees changed their scanning patterns in response to those facial actions, whereas humans maintained intense eye viewing across the expressions. Finally, we discuss how these face-scanning patterns are related to species-specific forms of facial communication in chimpanzees and humans, and suggest that both species have unique eye movement strategies for interactions with conspecifics. Author Affiliation: (a) Primate Research Institute, Kyoto University, Japan (b) Japan Society for the Promotion of Science, Japan Article History: Received 27 August 2009; Revised 22 September 2009; Accepted 20 October 2009 Article Note: (miscellaneous) MS. number: 09-00563

To authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.1468-2303.2009.00518.x Byline: ROBIN KELSEY (1) Keywords: chance; photography; photojournalism; animals; Joe Rosenthal; Henri-Cartier Bresson; Russell Maloney Abstract: ABSTRACT The role of chance in producing a picture by snapping a shutter release before a complex and quickly changing scene weakens the bond between the historic action photograph and the meanings it is routinely asked to bear. To appreciate this problem and to understand the array of popular notions that have been marshaled to finesse or suppress the role of chance in photographic production, I consider the case of Joe Rosenthal's 1945 photograph of American servicemen raising a flag on Iwo Jima. The analysis pushes the production of this famous photograph through a series of zoological analogies: Is it like a fisherman reeling in a trophy catch? Like a cat pouncing on a mouse or a spider setting a trap for a fly? Like a pig pushing its snout through the dirt? Like chimpanzees banging at typewriters? These analogies are playful but also serious. We need new models for understanding the production of the historic action photograph because the predominant modern and postmodern approaches to that production have suppressed the role of chance. Whereas the modern regime tends to understand the historic action photograph as an inspired flash of history, the postmodern regime tends to understand it as a discursive effect. Entertaining the notion that such a photograph is instead a stochastic result leads to a new conception of photography and its relationship to history. Chance emerges as a third kind of photographic madness, alongside the industrial madness decried by Charles Baudelaire and the indexical madness that moved Roland Barthes. Author Affiliation: (1)Harvard University

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.lmot.2008.11.002 Byline: Michael J. Beran (a), Chasity L. Ratliff (b), Theodore A. Evans (a) Keywords: Chimpanzees; Pan troglodytes; Natural choice; Selective value effect; Foraging; Decision-making Abstract: In three experiments, four chimpanzees made choices between two visible food options to assess the validity of the selective value effect (the assignment of value to only the most preferred type of food presented in a comparison). In Experiment 1, we established that all chimpanzees preferred single banana pieces to single apple pieces before presenting the critical test. In this test two chimpanzees preferred a mix of one banana piece and one apple piece to a single banana piece when both banana pieces were approximately the same size, but two chimpanzees were indifferent between the two options, exhibiting the selective value effect. In Experiment 2, when the banana pieces in both options were more closely equated in size, the chimpanzees were biased to choose the single banana piece over the mixed array even though this was the smaller total amount of food. However, in Experiment 3, when we introduced longer intervals between each trial, the chimpanzees preferred the mixed set and thus the larger total amount of food. The results demonstrate that only some chimpanzees exhibit the choice pattern indicative of the selective value effect, and they do so only when item size is not carefully controlled and trials are presented quickly in succession. Thus, the behavior pattern originally labeled the selective value effect may actually be explained by a combination of chimpanzees' sensitivity to small differences in preferred food amount and chimpanzees tendency to avoid less preferred foods that would delay the acquisition of further preferred food items. Author Affiliation: (a) Language Research Center, Georgia State University, University Plaza, Atlanta, GA 30302, USA (b) Southeast Missouri State University, Cape Girardeau, MO, USA Article History: Received 2 September 2008; Revised 25 October 2008

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.anbehav.2008.12.014 Byline: Emily E. Wroblewski (a), Carson M. Murray (b), Brandon F. Keele (c), Joann C. Schumacher-Stankey (a), Beatrice H. Hahn (c), Anne E. Pusey (a) Abstract: Competition for fertile females determines male reproductive success in many species. The priority of access model predicts that male dominance rank determines access to females, but this model has been difficult to test in wild populations, particularly in promiscuous mating systems. Tests of the model have produced variable results, probably because of the differing socioecological circumstances of individual species and populations. We tested the predictions of the priority of access model in the chimpanzees of Gombe National Park, Tanzania. Chimpanzees are an interesting species in which to test the model because of their fission-fusion grouping patterns, promiscuous mating system and alternative male mating strategies. We determined paternity for 34 offspring over a 22-year period and found that the priority of access model was generally predictive of male reproductive success. However, we found that younger males had higher success per male than older males, and low-ranking males sired more offspring than predicted. Low-ranking males sired offspring with younger, less desirable females and by engaging in consortships more often than high-ranking fathers. Although alpha males never sired offspring with related females, inbreeding avoidance of high-ranking male relatives did not completely explain the success of low-ranking males. While our work confirms that male rank typically predicts male chimpanzee reproductive success, other factors are also important; mate choice and alternative male strategies can give low-ranking males access to females more often than would be predicted by the model. Furthermore, the success of younger males suggests that they are more successful in sperm competition. Author Affiliation: (a) Jane Goodall Institute's Center for Primate Studies, Department of Ecology, Evolution and Behavior, University of Minnesota, Twin Cities, MN, U.S.A. (b) Lester E. Fisher Center for the Study and Conservation of Apes, Lincoln Park Zoo, Chicago, IL, U.S.A. (c) Departments of Medicine and Microbiology, University of Alabama at Birmingham, AL, U.S.A. Article History: Received 19 August 2008; Revised 23 September 2008; Accepted 8 December 2008 Article Note: (miscellaneous) MS. number: A08-00544R

Twenty five adult chimpanzee skeletons (Pan troglodytes verus) of known age and sex (15 females, 10 males) from a long-term study site in Tai National Park, Cote d'Ivoire present new data on variation. These skeletons provide a rare opportunity to measure the cranium and postcranium from the same individuals. We compare measurements and indices of the Tai sample with those of relatively complete Pan troglodytes schwein-furthii skeletons from Gombe National Park, Tanzania. Measurements of Pan paniscus are included as an outside comparison. The Tai and Gombe samples are analyzed by sex; combined sex samples are compared between the two groups, and the two sexes to each other. Tai females and males do not differ in most long bone lengths or in pelvic dimensions, but do differ significantly in cranial capacity, facial measurements, clavicle length, scapular breadth, and femur length. Gombe females and males differ significantly in some facial measurements and in scapular breadth. In combined sex samples, Tai individuals have lower cranial capacity, longer palate and mandible, and greater dimensions in the trunk and limb lengths. Tai females account for most of the variation; males differ from each other only in greater length of humerus and femur. The Tai skeletons provide new data for assessing individual variation and sexual dimorphism within and between populations and species. The combination of cranial and postcranial data provides a clearer picture of chimpanzee intraspecific and interspecific variation than can be gained from either data set alone. KEY WORDS skeletal biology; Tai chimpanzees; Gombe chimpanzees; sex differences; population variation

Sperm competition occurs when the gametes of or more males compete for opportunities to fertilize a given set of ova. Previous studies have demonstrated that certain morphological characteristics are affected by sperm competition intensity (e.g. relative testes size and sperm midpiece volume). This study examined whether aspects of sperm energetics may also be affected by sexual selection. We compared the membrane potential of mitochondria in live sperm between H. sapiens (single partner mating system) and P. troglodytes (multiple partner mating system). Flow cytometry of sperm stained with the carbocyanine fluorescent dye JC-1 (an assay for mitochondrial membrane potential) revealed marked differences in red fluorescence intensity. P. troglodytes sperm showed significantly higher mitochondrial membrane potential. Mitochondria provide a substantial part of the energy required for sperm motility. A higher mitochondrial loading may therefore be associated with enhanced sperm motility and/or longevity. Additionally, examination of JC-1 red fluorescence levels before and after in vitro capacitation revealed further differences. Whereas chimpanzee sperm showed maintenance of membrane potential after capacitation (in some cases even an increase), sperm from humans consistently showed reduction in membrane potential. These results indicate that the sperm of human beings and chimpanzees exhibit marked differences in mitochondrial function, which are affected by selection pressures relating to sperm competition and that these pressures differ significantly between humans and chimpanzees. Am J Phys Anthropol 134:274-280, 2007. KEY WORDS hominoid; reproduction; sperm competition

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.anbehav.2006.07.016 Byline: Lydia M. Hopper, Antoine Spiteri, Susan P. Lambeth, Steven J. Schapiro, Victoria Horner, Andrew Whiten Abstract: Multiple regional differences in tool use have been identified among wild chimpanzees, Pan troglodytes, but the hypothesis that these represent traditions, transmitted through social learning, is difficult to substantiate without experimentation. To test chimpanzees' capacity to sustain traditions, we seeded alternative tool use techniques in single individuals in different captive groups. One technique, 'Lift', spread in the group into which it was introduced and not in chimpanzees who saw no model or whose group was seeded with the alternative technique, 'Poke'. Poke was also not discovered by control animals tested individually. However, Poke emerged spontaneously in the Lift group and became dominant in both groups, regardless of the founder's Lift or Poke technique. Accordingly, this study demonstrated a statistically significant, differential spread of alternative techniques through social learning, yet no clear separation of traditions, unlike an earlier study with a different population of chimpanzees. This difference may be attributable to prior experience with relevant tools. In further experiments we investigated the basis of the social learning evident in acquisition of the Lift technique, using 'ghost' conditions in which the task was operated automatically rather than by a chimpanzee. Differential movement of the feeding device either by itself or with the tool coupled to it was not sufficient for learning to occur. It appears necessary for a chimpanzee to observe another chimpanzee performing the Lift technique for transmission to ensue. Author Affiliation: (a) Centre for Social Learning and Cognitive Evolution, and Scottish Primate Research Group, School of Psychology, University of St Andrews, U.K. (a ) Department of Veterinary Sciences, The University of Texas M.D. Anderson Cancer Center, U.S.A. Article History: Received 7 December 2005; Revised 20 January 2006; Accepted 21 July 2006 Article Note: (miscellaneous) MS. number: 8772R

Testosterone is a steroid hormone with diverse effects on male reproductive function and behavior. The relationship between testosterone and social behavior such as mating and aggression has been investigated in a variety of primate species, but few such studies have been conducted on chimpanzees, and even fewer on primates during the juvenile and adolescent periods. This study explores the relationship between baseline urinary testosterone and behavioral variables including dominance rank, rates of aggression toward peers, and behavioral style in 16 juvenile and adolescent male chimpanzees (Pan troglodytes) living at the New Iberia Research Center in Louisiana. Behavioral observations and urine collection occurred during four research periods, each a year apart. After correcting for the positive association between testosterone and age, testosterone was positively associated with both dominance rank and rates of aggression directed at others. It was negatively associated with rates of aggression received. Individuals scoring highest in the 'mellow' behavioral style component showed higher levels of testosterone than individuals scoring lowest in this component, an effect that may be partially due to the confounding effect of rank. The results of this study suggest that hormonal changes during the period preceding adulthood are not simply programmed physiological processes tied primarily to age-related change, but that important age-independent relationships with behavior also exist. KEY WORDS hormones; androgens; personality; primates; social behavior

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.anbehav.2005.09.009 Byline: Ian C. Gilby Abstract: Sharing food with nonkin is detrimental to a food donor's fitness, unless it is matched by compensatory benefits. I evaluated two explanations for nonkin meat sharing among wild chimpanzees, Pan troglodytes schweinfurthii. Reciprocal exchange proposes that a possessor relinquishes food in exchange for past or future sharing or for items of a different currency (e.g. grooming, alliances or copulations). The second hypothesis is the sharing-under-pressure/harassment model, which proposes that an individual shares to avoid the costs of defending a food item against persistent beggars. At Gombe National Park, Tanzania, I collected dyadic grooming and association data during focal follows of adult male chimpanzees. I videotaped meat-eating bouts, subsequently extracting detailed begging and sharing data. There was mixed support for the reciprocal exchange hypothesis. Sharing with males was not influenced by overall association and grooming rates. Female sexual receptivity did not affect the probability of sharing, nor did sharing increase the probability of mating. Meat possessors shared larger amounts, and were more likely to share actively with frequent female grooming partners. However, this pattern may have resulted from increased harassment by these individuals. In contrast, the sharing-under-pressure hypothesis was consistently supported: the possessor's feeding rate decreased with the number of beggars, the probability of sharing increased with the occurrence and duration of harassment, and harassment decreased following sharing events. I conclude that the pattern of meat sharing among the Gombe chimpanzees is largely explained by the sharing-under-pressure hypothesis, while the significance of reciprocal exchange remains unclear. Author Affiliation: Department of Ecology, Evolution and Behavior, University of Minnesota, U.S.A. Article History: Received 26 April 2005; Revised 19 July 2005; Accepted 29 September 2005 Article Note: (miscellaneous) MS. number: A10141R

Due to the predominance of teeth in the fossil record, dental characters are commonly used in diagnosing fossil species. In this study, dental characters are used in differentiating the known species, subspecies and populations of extant chimpanzees. By using dental characters to sort chimpanzees into their known taxonomic groups, the aim is to provide a test case for examining the utility of dental characters in differentiating extant species, with implications for the diagnosis and differentiation of fossil species. A total of 342 specimens of Pan including Pan paniscus (n=45), Pan troglodytes verus (n =73), Pan troglodytes troglodytes (n =135) and Pan troglodytes schweinfurthii (n=89) were studied from museums in the USA and Europe. Based on biogeographic data and previous studies on geographic variation, these species and subspecies were further divided into nineteen populations. Characters on the occlusal surface of teeth, particularly the kind used in fossil species differentiation, were studied by taking measurements either directly on the specimen or on digital images of the occlusal surface. About two hundred dental metric characters were studied on each specimen. After applying size adjustments to these data using the Geometric Mean, univariate statistical tests such as one-way Anova and the F-ratio, and multivariate statistical tests such as discriminant analysis and principal components analysis were performed on both the size-adjusted and non-size-adjusted data. The results of these analyses indicate that the two species of Pan, Pan troglodytes and Pan paniscus are classified with accuracy of about 90%. The accuracy is higher with non-size-adjusted data. The three commonly recognized subspecies of Pan troglodytes, P. t. verus, P. t. troglodytes and P. t. schweinfurthii are classified with accuracy of at least 60%. Classification accuracy for the populations drops significantly, with accuracy being higher for certain tooth types. This study is supported by grants from the Sokol Travel Award New York University, National Science Foundation, Wenner-Gren Foundation, L. S. B. Leakey Foundation, and a National Science Foundation award to NYCEP.