Observation of drinking behaviour in the Ursus arctos marsicanus at a tree cavity (dendrotelm) in the central...

Tree cavities that accumulate water (dendrotelms) represent ecologically important microhabitats and can serve as critical drinking sites for wildlife, particularly under increasing drought conditions. Although their use by birds and small mammals is well documented, interactions involving large carnivores in temperate forests remain largely unexplored. Here, based on the available literature, we describe what appears to be the first report of a paw-mediated drinking behaviour in the critically endangered Marsican brown bear (Ursus arctos marsicanus) recorded in the central Apennines (Italy). Camera-trap monitoring of a beech (Fagus sylvatica) tree over a five-month period revealed that bears typically drank by immersing the muzzle into the cavity during summer, when water levels were high. In early autumn, however, reduced precipitation led to a drop in cavity water level, making direct access impossible. Under these constrained conditions, bears adopted an alternative technique: repeatedly inserting a forepaw into the cavity, wetting it, and licking the water from the paw. This paw-mediated behaviour, observed in two prolonged sessions (14-16 min each), reflects behavioural flexibility under restricted access to water. These observations broaden current understanding of drinking ecology and context-dependent behavioural variation in bears, and emphasize the role of dendrotelms as previously overlooked seasonal water resources for large mammals. Further monitoring is required to assess how widespread this behaviour is and under which environmental conditions it is likely to occur.