Departamento de Ecología y Geología, Facultad de Ciencias, Universidad de Málaga, 29071 Málaga, Spain.
Departamento de Biotecnología, Facultad de Ciencias, Universidad de Alicante, 03080 Alicante, Spain.
Biol Lett. 2020 Dec;16(12):20200792. doi: 10.1098/rsbl.2020.0792. Epub 2020 Dec 23.
The cave bear (.) was an iconic extinct bear that inhabited the Pleistocene of Eurasia. The cause of extinction of this species is unclear and to identify the actual factors, it is crucial to understand its feeding preferences. Here, we quantified the shape descriptor metrics in three-dimensional (3D) models of the upper teeth (P-M) of the cave bear to make inferences about its controversial feeding behaviour. We used comparative samples, including representatives of all living bear species with known diets, as a template. Our topographic analyses show that the complexity of upper tooth rows in living bears is more clearly associated with the mechanical properties of the items consumed than with the type of food. Cave bears exhibit intermediate values on topographic metrics compared with the bamboo-feeder giant panda () and specialists in hard mast consumption ( and ). The crown topography of cave bear upper teeth suggests that they could chew on tough vegetal resources of low quality with high efficiency, a characteristic that no living bear currently displays. Our results align with a climate-driven hypothesis to explain the extinction of cave bear populations during the Late Pleistocene.
洞熊（.)是一种已灭绝的标志性熊类，栖息在更新世的欧亚大陆。该物种灭绝的原因尚不清楚，要确定实际因素，了解其摄食偏好至关重要。在这里，我们量化了三维（3D）模型中上颌牙齿（P-M）的形状描述符指标，以推断其有争议的摄食行为。我们使用了包括所有已知具有特定饮食的现存熊类代表的比较样本作为模板。我们的地形分析表明，现存熊类上颌牙齿的排列复杂性与所消耗物品的力学特性的关系比与食物类型的关系更为密切。与食竹的大熊猫（.)和硬壳果专门摄取者（ 和 ）相比，洞熊在地形学指标上的数值处于中间位置。洞熊上颌牙齿的冠顶地形表明，它们能够高效地咀嚼低质量的坚韧植物资源，这是目前没有任何现存熊类具备的特征。我们的研究结果与一种气候驱动的假说一致，该假说可以解释更新世晚期洞熊种群的灭绝。
