One of the specimens of brown bear, Ursus arctos, studied /
A study from the Museum of Natural Sciences indicates that these mammals not only communicate through chemical and acoustic signalling, but also tear the bark off trees to give information about their size.
When a bear scratches or nibbles the bark of a tree until it is torn off, it is issuing a visual warning to its adult congeners to tell them to be very careful with it, that these forests are full of specimens that are not willing to let another shade them, let alone in mating season. This is reflected in an investigation by the National Museum of Natural Sciences (MNCN), which, for the first time, “provides evidence” that, in addition to communication through chemical signals, brown bears, Ursus arctos, perform visual signals by tearing off the bark of certain trees to communicate.
The study led by the MNCN and in which the Doñana Biological Station (EBD) and the Mixed Institute for Biodiversity Research (IMIB), all from the CSIC, participate, shows that visual signals are made exclusively by adult males and only They are linked to the reproductive needs of the species.
For this article, which is published this Tuesday in the ‘Journal of Mammalogy’, the team has worked with the brown bear population of the Cantabrian mountain range using photos and a video trapping system. The images obtained have allowed them to analyze the behavior of several dozen individuals, including the 13 adult males responsible for leaving marks on the trees. “For a long time it has been considered that communication between mammals was essentially limited to chemical and acoustic signalling”, contextualizes the MNCN researcher Vincenzo Penteriani. “This experimental work offers, for the first time, evidence for the existence of a new communication channel for this species: visual signaling by removing part of the bark from the trunk of particularly visible trees,” he continues.
The status of the male
These visual markings, which they make by scratching and biting the bark, seem to have a very specific meaning since they are only made by adult males during the mating season. The team points out that they could provide information such as the size of the individual, which in the end is a way of making explicit the dominance status of each male in search of mating opportunities. This is information that complements that provided by chemical signals that were already known.
“Understanding the meaning of this form of communication not only represents an advance in our understanding of animal communication, but can also help us to easily locate the areas frequented by bears during the mating season. Crucial information for the conservation and management plans of the species”, ditch Penteriani.
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