Safe in the heights: trees as safer sites for female jaguars and their cubs in the Pantanal

Abstract

While the use of trees has been widely documented for most of the big cats, this information is scant for the jaguar (Panthera onca). In this study, we investigated the use of trees by jaguars, evaluating different underlying reasons as well as the frequency of tree use based on sex, age, and reproductive status. Data were obtained from 2013 to 2020 through a combination of direct observations during fieldwork and camera trapping focused on this behavior in the Brazilian Pantanal. We documented 252 climbing events (176 direct observations, 76 camera captures). Using only camera trapping data to avoid observers’ influence on jaguar behavior, we fitted generalized linear mixed models (GLMM) with jaguar identity as a random factor to test the effects of age, sex, and presence of conspecifics in the odds of animals climbing trees. We also used a generalized linear model (GLM) to test the effect of adult body weight on jaguar tree climbing probability. Age and presence of conspecifics were the most important drivers of jaguar climbing behavior in the study area, with cubs being more likely to climb trees than adults of either sex (odds ratio = 7.91, p < 0.001), and the presence of conspecifics, irrespective of age and sex, accentuated that behavior (odds ratio = 3.26, p < 0.005). Adult females (especially the lighter ones) and cubs were commonly recorded through direct observation on trees, a similar trend to our GLMM that showed a marginally negative effect of body weight on jaguar tree climbing probability. Only a few adult male jaguars ascended trees, and in all cases, these males were following females in heat. We suggest that trees are vertical extensions inside jaguar home ranges and may be safe refuges for resting and for protecting offspring against potential threats, including the harassment of large adult males.