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- Effects of an extreme weather event on primate populationsPublication . Beardmore-Herd, Megan; Palmer, Meredith S.; Gaynor, Kaitlyn M.; Carvalho, SusanaObjectives: With contemporary, human-induced climate change at a crisis point, extreme weather events (e.g., cyclones, heat waves, floods) are becoming more frequent, intense, and difficult to predict. These events can wreak rapid and significant changes on ecosystems; thus, it is imperative to understand how wildlife communities respond to these disruptions. Primates are perceived as being a largely adaptable order, but we often lack the quantitative data to rigorously assess how they are impacted by extreme environmental change. Leveraging detections from a long-term camera trap survey, this opportunistic study reports the effects of an extreme weather event on a little-studied population of free-ranging primates in Gorongosa National Park, Mozambique. Materials and Methods: We examined shifts in gray-footed chacma baboon (Papio ursinus griseipes) and vervet monkey (Chlorocebus pygerythrus) spatial distribution and relative abundance following Cyclone Idai—a category four tropical cyclone that struck Mozambique in March 2019. Results: Baboon spatial distributions were impacted in the first month after the cyclone, with more detections in areas where flooding was less severe. Spatial distributions renormalized once floodwaters began to recede. We describe vervet monkey spa tial distribution trends, though sample size limitations inhibited statistical analysis. Primate relative abundance did not appear to substantially decrease following the cyclone, suggesting troops were able to adopt behavioral adjustments to evade rising floodwaters. Discussion: These findings highlight the behavioral flexibility of Gorongosa's primates and their ability to adapt to extreme—if temporary—disruptions, with implications for primate conservation in the Anthropocene and research into how rapid climatic events may have shaped primate evolution.
- Stone selection by wild chimpanzees shares patterns with Oldowan homininsPublication . Braun, D. R.; Carvalho, Susana; Kaplan, R. S.; Beardmore-Herd, Megan; Plummer, T.; Biro, D.; Matsuzawa, T.The use of broad tool repertoires to increase dietary flexibility through extractive foraging behaviors is shared by humans and their closest living relatives (chimpanzees, Pan troglodytes). However, comparisons between tool use in ancient human ancestors (hominins) and chimpanzees are limited by differences in their toolkits. One feature shared by primate and hominin toolkits is rock selection based on physical properties of the stones and the targets of foraging behaviors. Here, we document the selectivity patterns of stone tools used by wild chimpanzees to crack nuts at Bossou, Guinea, through controlled experiments that introduce rocks unknown to this population. Experiments incorporate specific rock types because previous studies document hominin selection of these lithologies at Kanjera South 2 Ma. We investigate decisions made by chimpanzees when selecting stones that vary in their mechanical propertiesdfeatures not directly visible to the individual. Results indicate that the selection of anvils and hammers is linked to task-specific mechanical properties. Chimpanzees select harder stones for hammers and softer stones for anvils, indicating an understanding of specific properties for distinct functions. Selectivity of rock types suggests that chimpanzees assess the appropriate materials for functions by discriminating these 'invisible' properties. Adults identify mechanical properties through individual learning, and juveniles often reused the tools selected by adults. Selection of specific rock types may be transmitted through the reuse of combinations of rocks. These patterns of stone selection parallel what is documented for Oldowan hominins. The processes identified in this experiment provide insights into the discrete nature of hominin rock selection patterns in Plio-Pleistocene stone artifact production.