Brown bear communication hubs: patterns and correlates of tree rubbing and pedal marking at a long-term marking site

Eloy Revilla; Damián Ramos Fernández; Alberto Fernández-Gil; Agnieszka Sergiel; Nuria Selva; Javier Naves

doi:10.7717/peerj.10447

Brown bear communication hubs: patterns and correlates of tree rubbing and pedal marking at a long-term marking site

PeerJ. 2021 Jan 29:9:e10447. doi: 10.7717/peerj.10447. eCollection 2021.

Authors

Eloy Revilla¹, Damián Ramos Fernández², Alberto Fernández-Gil¹, Agnieszka Sergiel³, Nuria Selva³, Javier Naves¹

Affiliations

¹ Department of Conservation Biology, Estación Biológica de Doñana CSIC, Seville, Spain.
² Consejería de Infraestructuras, Ordenación del Territorio y Medio Ambiente, Gobierno del Principado de Asturias, Oviedo, Spain.
³ Institute of Nature Conservation, Polish Academy of Sciences, Krakow, Poland.

Abstract

Chemical communication is important for many species of mammals. Male brown bears, Ursus arctos, mark trees with a secretion from glands located on their back. The recent discovery of pedal glands and pedal-marking at a site used for tree-rubbing led us to hypothesize that both types of marking form part of a more complex communication system. We describe the patterns of chemical communication used by different age and sex classes, including differences in the roles of these classes as information providers or receivers over four years at a long-term marking site. Using video recordings from a camera trap, we registered a total of 285 bear-visits and 419 behavioral events associated with chemical communication. Bears visited the site more frequently during the mating season, during which communication behaviors were more frequent. A typical visit by male bears consisted of sniffing the depressions where animals pedal mark, performing pedal-marking, sniffing the tree, and, finally, rubbing against the trunk of the tree. Adult males performed most pedal- and tree-marking (95% and 66% of the cases, respectively). Males pedal-marked and tree-rubbed in 81% and 48% of their visits and sniffed the pedal marks and the tree in 23% and 59% of visits, respectively. Adult females never pedal marked, and juveniles did so at very low frequencies. Females rubbed against the tree in just 9% of their visits; they sniffed the tree and the pedal marks in 51% and 21% of their visits, respectively. All sex and age classes performed pedal- and tree-sniffing. There were significant associations between behaviors indicating that different behaviors tended to occur during the same visit and were more likely if another individual had recently visited. These associations leading to repeated marking of the site can promote the establishment of long-term marking sites. Marking sites defined by trees and the trails leading to them seem to act as communication hubs that brown bears use to share and obtain important information at population level.

Keywords: Chemical communication; Marking behaviour; Scent marking; Tree marking; Ursus arctos.

Grants and funding

Eloy Revilla, Alberto Fernández-Gil, Nuria Selva, and Javier Naves were supported by projects CGL2017-83045-R AEI/FEDER EU, by the Agencia Estatal de Investigación from the Ministry of Economy, Industry and Competitiveness, Spain co-financed with FEDER to Eloy Revilla; Project 20166422 from the Principado de Asturias–Consejería de Agroganadería y Recursos Autóctonos to Eloy Revilla, Javier Naves and Alberto Fernández. Nuria Selva and Agnieszka Sergiel were supported by the National Centre for Research and Development (GLOBE, POL-NOR/198352/85/2013) and by the National Science Centre in Poland under projects BearConnect BiodivERsA 2016/22/Z/NZ8/00121 and project DEC-2013/08/M/ NZ9/00469. The publication fee was paid by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.