European cave bears (Ursus ingressus), which went extinct roughly 24,000 years ago, hibernated for longer periods of time than other living bears do in order to survive the extended winters of the Last Glacial Period. Three-dimensional biomechanical simulations demonstrate that these bears had large sinuses that aided in decreasing heart rate, body temperature, and blood pressure during hibernation, according to a study published on April 1 in Science Advances, but the expanded sinuses also decreased the structural stability of the bears’ skulls, impeding their ability to hunt and forage and effectively restricting them to an herbivorous diet.
The authors of the paper argue that the combination of both long periods of hibernation and a restrictive diet may have ultimately led to the cave bears’ demise.
A. Pérez-Ramos et al., “Biomechanical simulations reveal a trade-off between adaptation to glacial climate and dietary niche versatility in European cave bears,” Science Advances, doi:10.1126/sciadv.aay9462, ...
