Rodent gnawing over fresh, dry and thermo altered bones: an experimental study with archaeological implications at El Mirador Cave (Atapuerca, Spain) Francesc Marginedas a,b , Antonio Rodríguez-Hidalgo a,b,c and Palmira Saladié a,b,d a UCO de Zooarqueologia i Tafonomia, Institut Català de Paleoecología Humana i Evolució Social (IPHES-CERCA), Tarragona, Spain; b Área de Prehistòria, Universitat Rovira i Virgili (URV), Tarragona, Spain; c IDEA (Instituto de Evolución en África), Madrid, Spain; d Unit Associated to CSIC. Departamento de Paleobiologia. Museo Nacional de Ciencias Naturales, Madrid, Spain ABSTRACT Rodents gnaw bones to wear down their upper and lower incisors, which grow continuously. These gnawing marks are conspicuous and have long been identifed in the fossil record. Archaeological taphonomy studies link modifcations made by rodents to weathered and dried bones, while forensic taphonomy indicate that rodents also act on fresh corpses, consuming fesh and other tissues as well as fresh bones. Although these two approaches are complementary, there is a lack of information on how rodents modify bones in states other than dry or fresh. This experimental study aims to fll this gap in the research, describing modifcations left by rodents (Mus musculus) to fresh, boiled, carbonised, calcined, and dry bones. Our results indicate that rodents modify bones regardless of their state, and that the most intense gnawing occurs on bones containing fat. During the study, the pedestalling phenomena emerged as a characteristic modifcation produced only on fresh and boiled samples. We applied our results to the study of the human remains from El Mirador Cave (Atapuerca, Spain) and identifed pedestalling for the frst time in the archaeological record. This modifcation may have been favoured by the presence of fatty bones laying exposed on the surface of the site. ARTICLE HISTORY Received 03 May 2022 Accepted 01 July 2022 KEYWORDS Forensic taphonomy; rodentia; pedestalling; bone surface modifications; Mus musculus Introduction Rodents gnaw bones, wood, and other hard materials to wear down their upper and lower incisors, which grow continuously (Brain 1981; Samuels 2009). However, gnawing dry bones has also been linked to the nutritional contribution of minerals like calcium and phosphorous (Carlson 1940; Coventry 1940; Dart 1958). While biting, rodents anchor their upper incisors and move the lower ones forward and upward, repeatedly tearing fibres and tissues (Haglund 1997). From an archaeological perspective, rodent activity has been identified through grooves produced by the incisors on the surface of bones. These modifications have also been described as channels; striae; windows; and straight, parallel and flat-bottomed grooves (Bonnichsen 1979; Shipman and Rose 1983; Johnson 1985). The activity of these animals has primarily been associated with the activity of porcupines, which not only modify bones, but also transport them to their dens (Brain 1981). Some indicators that have linked this activity with a diagenetic phase include the pre- sence of modifications to diagenetic fractures and a change in colour in gnawed areas (Bautista et al. 2010). Occasionally, the presence of these modifications has led to the identification of the species or group of modifying animals. Porcupines, for example, have been identified in Crag-Bed deposits (East Anglia) (Sutcliffe and Collings 1972), Sterkfontein Member 5 (South Africa) (Brain 1981) and Galería-Atapuerca (Spain) (Fernández-Jalvo and Andrews 2016). In other studies, the actors have been described as small rodents or rodents in general, such as in shelters and caves from Pleistocene to Holocene levels (e.g., Saladié 2009; Bautista et al. 2010; Gabucio et al. 2012). According to Fernández-Jalvo and Andrews (2016), although rats do consume bone for food, rodents tend to gnaw on bones with several years of subaerial exposure. As such, their presence is an indicator of the extended abandonment of sites by humans. Forensic taphonomy studies have also documented a wide variety of cases in which rodent activity has been noted on flesh and fresh and dry bone (Haglund 1992, 1997; Tsokos et al. 1999; Tsokos and Schulz 1999; Klippel and Synstelien 2007; Reddy and Lowenstein 2011; Pokines 2014, 2015, 2016). The consumption of green bone and meat has been linked to nutritional needs and has often been associated with omnivorous rodents like mice or rats (Pokines 2022). These animals have been known to ingest soft tissue, delicate bone areas like the epiphysis and nasal margins. This activity leaves striae or grooves, a two-point pattern resulting from anchoring the upper incisors, and the pedestalling phenomenon (Haglund 1992, 1997; Tsokos et al. 1999; Klippel and Synstelien 2007; Toledo et al. 2017; Pokines 2022). The consumption of meat and fresh bones has mainly been associated with black rats (Rattus rattus), Norway rats (Rattus norvegicus) and house mice (Mus musculus) (Landry 1970; Haglund 1992, 1997; Tsokos et al. 1999; Klippel and Synstelien 2007; Pokines et al. 2017), although this activity has also been documented in other rodents, including eastern grey squirrels (Sciurus carolinensis), chip- munks (Tamias striatus) and wood mice (Apodemus sylvaticus) (Young et al. 2014; Pokines and Pollock 2018; Pokines 2022). The consumption of dry bone has been related to many rodent species and even lagomorphs (Pokines et al. 2017), mostly associated with incisor sharpening and the consumption of minerals (Pokines 2022). Considering the archaeological studies and their interpretations, as compared to forensic science studies, it is shown that there is a lack of evidence in the archaeological record that allows us to discuss gnawing on fresh bones by rodents. In fact, Haglund, CONTACT Francesc Marginedas francescm63@gmail.com Institut Català de Paleoecología Humana i Evolució Social (IPHES-CERCA), Tarragona, Spain; Área de Prehistòria, Universitat Rovira i Virgili (URV), Tarragona, Spain HISTORICAL BIOLOGY https://doi.org/10.1080/08912963.2022.2098487 © 2022 Informa UK Limited, trading as Taylor & Francis Group Published online 07 Jul 2022