A study of bears in the Pyrenees of Lleida helps to clarify how the behaviour of these animals was in prehistory

It has been found that bears are quite different from other carnivorous predators possibly because of the shape of their paws and their omnivorous diet

This work identifies the authorship of bites and fractures produced by different carnivores there thanks to the shooting of bears consuming carcasses and the involvement of the Equips de Seguiment de l’Ós Bru del Conselh Generau d’Aran i del Pallars Sobirà

The results can be applied in the Atapuerca Caves and Cova de les Llenes (Pallars Jussà, Lleida)

PHOTOS

Bears are one of the most iconic prehistoric animals. Their cave habits are well known, particularly those related to hibernation, which makes them very common in the oldest archaeological sites. Their behaviour, however, is still largely unknown, especially as carnivorous consumers of the other animals. In fact, in many fields their presence has been inferred from bites on the bones of other animals, including dead bears during hibernation. However, the characterization of these animals from a taphonomic point of view (study of the brands associated with the bones and teeth) is still an unresolved archaeological assessment. A new study published in the journalPLOS ONE lead by IPHES (Institut Català de Paleoecologia Humana i Evolució Social) aims to clarify this subject.

The archaeologist Jordi Rosell, researcher and professor at the Universitat Rovira i Virgili of Tarragona, IPHES member and one of the signers of the article, highlights one of the singularities of this research now presented: “Some previous studies based their conclusions on very small samples or work done with captive breeding animals, which have a quite different behaviour of the wild. We have studied 17 carcasses eaten by bears in the Pyrenees of Lleida (Spain) and were able to identify patterns of consume of the whole corpses from these animals”.

The study has been carried out by Jordi Rosell, Maite Arilla (also IPHES), in collaboration with Ruth Blasco, post-doctoral researcher Beatriu of Pinós-A, co-financed by the European Union through the Acciones Marie Curie of the 7th Programme framework for I + D; Manuel Domínguez Rodrigo from the Complutense University of Madrid and Travis R. Pickering, University of Wiskonsin.

The objective was to characterize the bears as carnivores, to distinguish them from other predators and hominids. “The great virtue of this research is that it will serve to help to identify not only whether a body found in a site was eaten by a bear, or what kind of carnivore did it,” said Jordi Rosell.

Distinguishing the types of bites

Bears are very abundant in the prehistoric sites, especially in caves, and as carnivores produce many disturbances, as they die inside after hibernation, the bodies of the deceased bears are eaten, mixed with the garbage left by hominids, etc. “In this case,  continued Rosell, “we have focused on a very specific aspect: consumption of whole carcasses to see what could happen when a bear find one of them and what types of bites left. After doing this work, we are now able to check whether the observed behaviour of the actual bears was reproduced in the past species, such as the cave bear, or even earlier”.

The goal has been achieved through the collaboration of the Equips de Seguiment de l’Ós Bru del Conselh Generau d’Aran i del Pallars Sobirà Cova de les Llenes (Pallars Jussà, Lleida) and of DAAM (Departament d’Agricultura, Ramaderia, Pesca, Alimentació i Medi Ambient) de la Generalitat de Catalunya, which has allowed 17 carcasses eaten by bears in the Pyrenees of Lleida. In addition, thanks to them, the researchers have obtained the images of natural dead animals and those scavenged by bears from photo-trap and video-trap, and used the images to track the patterns of consumption of these animals. Simultaneously,  the animal carcasses that were hunted by the bears were collected and studied.

Video and photo traps

The photo-trap is where cameras with motion sensors are placed around the corpses, so that a bear is captured in pictures and you can follow its process of consumption. “Obviously, this can only be done in cases of scavengers when the guards know about the natural death of an animal. They go and put the cameras”, said Jordi Rosell.

Bears skin corpses

According to this research, bears begin the eating sequence skinning corpses, “a phenomenon that has not been observed between any other carnivore”, said Jordi Rosell. “Then show a preference for the rib cage and the visceras contained, which consistently consume after fracturing the ribs and part of the vertebrae squashing with their front legs, or expanding them with their hands. In contrast, do not seem to show much interest in the muscle mass of the legs”, said the same archaeologist.

Statistical treatment

All these observations have enabled to establish comparisons, using a statistical treatment of the changes produced by bears on the bones of animals eaten (fractures and signs of bites) with those made by other European predators (wolves) and African (lions and hyenas). These data have also been obtained by some of the authors in previous works. “The results show bears as different carnivores from the others, which could be related to their physiology and their omnivorous habits, since these animals do not rely exclusively on meat to survive,” said Rosell.

Thus, this work is a global reference for interpreting the activities of different predators that are found in archaeological sites. Examples of the Iberian Peninsula where these results can be applied due to the abundance of these animals are the caves in Atapuerca (Burgos) or Cova de les Llenes (Pallars Jussà, Lleida)

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