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Because global climate change results in increasingly extreme temperatures and more frequent droughts, behavioral thermoregulation is one avenue by which species may adjust. Changes in activity patterns in response to temperature have been observed in a number of mammal species, but rarely have been investigated in humid tropical habitats. Here we examine the relationship between activity patterns and microclimate temperatures for white-lipped peccaries (Tayassu pecari , Tayassuidae, Cetartiodactyla) in four distinct biomes—the Cerrado, the Pantanal, the Atlantic Forest, and the Amazon. From 2013 to 2017, we monitored 30 white-lipped peccaries fitted with GPS collars that included accelerometers and temperature sensors. White-lipped peccaries were primarily diurnal, with peaks of activity in the morning and late afternoon, except in the Amazon where activity was high throughout the day. Total time active did not vary seasonally. White-lipped peccaries were significantly less likely to be active as temperatures increased, with the probability of being active decreasing by >49% in all biomes between 30 and 40°C. Our findings indicate that white-lipped peccaries are likely to be adversely impacted by rising temperatures, through being forced to reduce foraging time during their prime active periods. [ABSTRACT FROM AUTHOR]

White-lipped peccaries (WLPs; Tayassu pecari, Tayassuidae, Cetartiodactyla) are forest-dwelling ungulates critical to maintaining healthy Neotropical forest ecosystems through key aspects of their dietary behaviors, including seed predation and dispersal. Land-use change and deforestation threaten WLP access to food resources, and thus knowledge of how WLP diet varies spatially is necessary to frame conservation efforts for the species. Here, we use stable carbon (δ13C) and nitrogen (δ15N) isotopes from WLP hair and food resources to assess whether WLP diet varies among four regions in three Brazilian biomes: the Pantanal, the Cerrado, and the Atlantic Forest (semi-deciduous and ombrophilous), each varying in forest canopy cover, climatic characteristics, and degrees of agricultural impacts. We find that in all regions WLPs are consuming primarily C3 resources, with mean δ13C values ranging from −28.7‰ to −26.9‰. In the heavily fragmented semi-deciduous Atlantic Forest, δ13C values are the highest, and may indicate that some individuals are consuming a small amount of C4 crops or demonstrating increased levels of insectivory. A through-time comparison of WLP hair in the semi-deciduous Atlantic Forest suggests the recorded slight departure from an exclusive C3 diet may be a recent phenomenon, as hairs collected prior to the year 2000 have lower δ13C values than those collected in 2016. While some individual WLPs may slightly alter diet in heavily anthropogenically modified areas, C4 crops are not a main component of WLP diet. Our results suggest that WLPs are still highly dependent on forest resources, even in human-altered landscapes, and conservation and management plans for the species must consider these dietary needs in order to be successful. Queixadas (Tayassu pecari, Tayassuidae, Certartiodactyla) são ungulados florestais essenciais na manutenção das florestas Neotropicais, dado que sua dieta e comportamento de forrageio afetam a dispersão e predação de sementes e plântulas. A ocupação do solo e o desmatamento ameaçam populações de queixada e seu acesso a fontes de alimento. Dessa forma, informações mais detalhadas sobre a variação espacial da dieta de queixadas são importantes para guiar planos de conservação da espécie. No presente estudo, utilizamos isótopos estáveis de carbono (δ13C) e nitrogênio (δ15N) provenientes de amostras de pêlo de queixada e de recursos alimentares obtidos nas mesmas localidades para avaliar como a dieta de queixadas varia em quatro regiões de três biomas brasileiros: Mata Atlântica (ombrófila e semi-decídua), Cerrado e Pantanal, cada um representando valores distintos dentro de um gradiente de cobertura vegetal, características climáticas e graus de impacto antrópico. Nossos resultados revelam que, em todas regiões e biomas amostrados, queixadas consomem essencialmente recursos provenientes de plantas C3, com valores médios de δ13C variando de −28.7‰ a −26.9‰. Na Mata Atlântica semi-decídua, região mais fragmentada pela agricultura, resultados das amostras de pêlos apresentaram os valores mais altos de δ13C, indicando que alguns indivíduos podem estar consumindo pequenas quantidades de plantas C4 des plantações ou um aumento nas taxas de insetivoria. Uma análise temporal dos dados provenientes da Mata Atlântica semi-decídua sugere que o aumento nos valores de δ13C é um fenômeno recente, uma vez que os valores de δ13C de amostras de pêlos coletadas antes do ano 2000 são significativamente mais baixos do que as coletadas em 2016. Apesar desses indícios de que alguns indivíduos de queixada estejam alterando levemente sua dieta em regiões dominadas por monoculturas, estas não são o componente principal de sua dieta. Nossos resultados sugerem que queixadas ainda são altamente dependentes de recursos provenientes dos remanescentes florestais, mesmo em paisagens altamente modificadas, e planos de conservação e manejo da espécie devem considerar estas necessidades de sua dieta para que tenham sucesso. [ABSTRACT FROM AUTHOR]

Food caching is widespread among several animal species. Few studies have proposed that handling time should affect the evolution of caching behavior, especially under foraging time constraints. Nevertheless, to date, there has been no analytical support to the “handling time hypothesis.” In the present article, we use an analytical model to show that caching behavior may evolve as the result of shorter handling time caching relative to eating. We evaluate caching behavior under 3 fitness objectives (or environmental scenarios): maximizing energy consumed, maximizing and balancing energy consumed, and maximizing energy consumed under risk of predation. Our analyses reveal that under all 3 fitness objectives, caching behavior can evolve when caching time is shorter than eating time, to allow the animal to free up search time during the period when food is plentiful and postpone time spent handling to the period when food is scarce and search time is less valuable. That effect may be called “search time reallocation,” and it is still prevalent even if food decays. Our model provides predictions that can be field tested, adds to the debate of handling time and perishability hypotheses, and invites researchers to direct their focus toward understanding the evolutionary motives of caching behavior. [ABSTRACT FROM PUBLISHER]