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Indianapolis, IN, United States

Pontzer H.,Washington University in St. Louis | Raichlen D.A.,University of Arizona | Shumaker R.W.,Indianapolis Zoo | Shumaker R.W.,George Mason University | And 2 more authors.
Proceedings of the National Academy of Sciences of the United States of America

Energy is the fundamental currency of life - needed for growth, repair, and reproduction - but little is known about the metabolic physiology and evolved energy use strategies of the great apes, our closest evolutionary relatives. Here we report daily energy use in free-living orangutans (Pongo spp.) and test whether observed differences in energy expenditure among orangutans, humans, and other mammals reflect known differences in life history. Using the doubly labeled water method, we measured daily energy expenditure (kCal/d) in orangutans living in a large indoor/outdoor habitat at the Great Ape Trust. Despite activity levels similar to orangutans in the wild, Great Ape Trust orangutans used less energy, relative to body mass, than nearly any eutherian mammal ever measured, including sedentary humans. Such an extremely low rate of energy use has not been observed previously in primates, but is consistent with the slow growth and low rate of reproduction in orangutans, and may be an evolutionary response to severe food shortages in their native Southeast Asian rainforests. These results hold important implications for the management of orangutan populations in captivity and in the wild, and underscore the flexibility and interdependence of physiological, behavioral, and life history strategies in the evolution of apes and humans. Source

Samson D.R.,Duke University | Shumaker R.,Indianapolis Zoo | Shumaker R.,Indiana University Bloomington | Shumaker R.,George Mason University
Folia Primatologica

The nightly construction of a 'nest' or sleeping platform is a behavior that has been observed in every wild great ape population studied, yet in captivity, few analyses have been performed on sleep related behavior. Here, we report on such behavior in three female and two male captive orangutans (Pongo spp.), in a natural light setting, at the Indianapolis Zoo. Behavioral samples were generated, using infrared cameras for a total of 47 nights (136.25 h), in summer (n = 25) and winter (n = 22) periods. To characterize sleep behaviors, we used all-occurrence sampling to generate platform construction episodes (n = 217). Orangutans used a total of 2.4 (SD = 1.2) techniques and 7.5 (SD = 6.3) actions to construct a sleeping platform; they spent 10.1 min (SD-9.9 min) making the platform and showed a 77% preference for ground (vs. elevated) sleep sites. Comparisons between summer and winter platform construction showed winter start times (17:12 h) to be significantly earlier and longer in duration than summer start times (17:56 h). Orangutans should be provisioned with seasonally appropriate, high quality materials suitable for construction of sleeping platforms to increase sleep quality and improve animal health and welfare. © 2015 S. Karger AG, Basel. Source

Lameira A.R.,University Utrecht | Hardus M.E.,University of Amsterdam | Kowalsky B.,Heidelberg Zoo | De Vries H.,University Utrecht | And 6 more authors.
Journal of the Acoustical Society of America

One of the most apparent discontinuities between non-human primate (primate) call communication and human speech concerns repertoire size. The former is essentially fixed to a limited number of innate calls, while the latter essentially consists of numerous learned components. Consequently, primates are thought to lack laryngeal control required to produce learned voiced calls. However, whether they may produce learned voiceless calls awaits investigation. Here, a case of voiceless call learning in primates is investigated - orangutan (Pongo spp.) whistling. In this study, all known whistling orangutans are inventoried, whistling-matching tests (previously conducted with one individual) are replicated with another individual using original test paradigms, and articulatory and acoustic whistle characteristics are compared between three orangutans. Results show that whistling has been reported for ten captive orangutans. The test orangutan correctly matched human whistles with significantly high levels of performance. Whistle variation between individuals indicated voluntary control over the upper lip, lower lip, and respiratory musculature, allowing individuals to produce learned voiceless calls. Results are consistent with inter- and intra-specific social transmission in whistling orangutans. Voiceless call learning in orangutans implies that some important components of human speech learning and control were in place before the homininae-ponginae evolutionary split. © 2013 Acoustical Society of America. Source

Lameira A.R.,University of Amsterdam | Hardus M.E.,University of Amsterdam | Bartlett A.M.,Princeton University | Shumaker R.W.,Indianapolis Zoo | And 4 more authors.

The evolutionary origins of speech remain obscure. Recently, it was proposed that speech derived from monkey facial signals which exhibit a speech-like rhythm of ∼5 open-close lip cycles per second. In monkeys, these signals may also be vocalized, offering a plausible evolutionary stepping stone towards speech. Three essential predictions remain, however, to be tested to assess this hypothesis' validity; (i) Great apes, our closest relatives, should likewise produce 5Hz-rhythm signals, (ii) speech-like rhythm should involve calls articulatorily similar to consonants and vowels given that speech rhythm is the direct product of stringing together these two basic elements, and (iii) speech-like rhythm should be experience-based. Via cinematic analyses we demonstrate that an ex-entertainment orangutan produces two calls at a speech-like rhythm, coined "clicks" and "faux-speech." Like voiceless consonants, clicks required no vocal fold action, but did involve independent manoeuvring over lips and tongue. In parallel to vowels, faux-speech showed harmonic and formant modulations, implying vocal fold and supralaryngeal action. This rhythm was several times faster than orangutan chewing rates, as observed in monkeys and humans. Critically, this rhythm was seven-fold faster, and contextually distinct, than any other known rhythmic calls described to date in the largest database of the orangutan repertoire ever assembled. The first two predictions advanced by this study are validated and, based on parsimony and exclusion of potential alternative explanations, initial support is given to the third prediction. Irrespectively of the putative origins of these calls and underlying mechanisms, our findings demonstrate irrevocably that great apes are not respiratorily, articulatorilly, or neurologically constrained for the production of consonant- and vowel-like calls at speech rhythm. Orangutan clicks and faux-speech confirm the importance of rhythmic speech antecedents within the primate lineage, and highlight potential articulatory homologies between great ape calls and human consonants and vowels. © 2015 Lameira et al. Source

Hogan J.N.,University of California at Davis | Miller W.A.,University of California at Davis | Cranfield M.R.,University of California at Davis | Ramer J.,Indianapolis Zoo | And 4 more authors.
Journal of Wildlife Diseases

Mountain gorillas (Gorilla beringei beringei) are critically endangered primates surviving in two isolated populations in protected areas within the Virunga Massif of Rwanda, Uganda, the Democratic Republic of Congo, and in Bwindi Impenetrable National Park in Uganda. Mountain gorillas face intense ecologic pressures due to their proximity to humans. Human communities outside the national parks, and numerous human activities within the national parks (including research, tourism, illegal hunting, and anti-poaching patrols), lead to a high degree of contact between mountain gorillas and wildlife, domestic animals, and humans. To assess the pathogen transmission potential between wildlife and livestock, feces of mountain gorillas, forest buffalo (Syncerus caffer nanus), and domestic cattle (Bos taurus) in Rwanda were examined for the parasites Giardia and Cryptosporidium. Giardia was found in 9% of mountain gorillas, 6% of cattle, and 2% of forest buffalo. Our study represents the first report of Giardia prevalence in forest buffalo. Cryptosporidium-like particles were also observed in all three species. Molecular characterization of Giardia isolates identified zoonotic genotype assemblage B in the gorilla samples and assemblage E in the cattle samples. Significant spatial clustering of Giardiapositive samples was observed in one sector of the park. Although we did not find evidence for transmission of protozoa from forest buffalo to mountain gorillas, the genotypes of Giardia samples isolated from gorillas have been reported in humans, suggesting that the importance of humans in this ecosystem should be more closely evaluated. © Wildlife Disease Association 2014. Source

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