AJP Featured Articles

Total Energy Expenditure in Captive Capuchins (Sapajus apella).

Authors: Wren Edwards, Elizabeth V. Lonsdorf, Herman Pontzer

Everyone knows that “burning off” that burger and fries means burning calories, but all animals need energy in the form of calories for our body’s daily maintenance tasks of cell repair, growth, digestion, reproduction, and thermal regulation. Primates are known for a suite of traits including large brains, complex social structure, and propensity for tool-use. In addition, they use on average 50% less energy than all other mammals during their daily activities. This project investigates how one previously unstudied species of New World monkey, the tufted capuchin (Sapajus apella), fits into this scheme. A significant proportion of the primate energy budget seems to be dedicated to the brain, and capuchins have a larger relative brain size than other related New World monkeys. Because of this, we hypothesized that capuchins would expend more energy. To test this hypothesis, we used a non-invasive technique called the doubly-labeled water method to accurately determine how much energy the monkeys were expending on a daily basis and we compared these results with previously recorded energy expenditure data from other primates. We found that while capuchins expended 54% less energy than non-primate mammals of similar size, they only exhibited marginally greater total energy expenditure than other New World monkeys. The physiological mechanisms underlying the diversity of brain size and life history among primates, and specifically within New World monkeys, remain poorly understood. Further metabolic research will advance our understanding of primate energetics, ecology, and evolution.

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Ten years of orangutan-related wildlife crime investigation in West Kalimantan, Indonesia.

Authors: Cathryn Freund, Edi Rahman, Cheryl Knott

Poaching for the pet trade is considered one of the main threats to orangutan survival, especially to the Bornean species (Pongo pygmaeus). However, there have been few attempts to quantify the number of individuals taken from the wild or to evaluate the drivers of the trade. Most orangutan poaching is thought to be opportunistic in nature, occurring in conjunction with deforestation for large-scale agriculture. Using data from our long-term wildlife crime field investigation program collected from 2004-2014, we evaluated the prevalence of orangutan poaching and its spatial distribution in and around Gunung Palung National Park, in the regencies (districts) of Ketapang and Kayong Utara, West Kalimantan, Indonesia. Over the project period, investigators uncovered 145 cases of orangutans being illegally held captive for the pet trade. There was a significant correlation between the extent of oil palm and the number of cases reported from each sub-district in the landscape, supporting the widely held hypothesis that orangutan poaching is opportunistic, and we found no evidence of orangutan trading rings (i.e. international traders) targeting Gunung Palung National Park. Over the past decade, there only has been one prosecution of orangutan trading in West Kalimantan, and weak law enforcement by Indonesian authorities remains the most significant challenge in addressing wildlife trade. We offer four recommendations to address this. As oil palm begins to expand into Africa, this study also may help predict how this will affect gorillas, chimpanzees, and bonobos, encouraging proactive conservation action.

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