Abstract
Since the late 1700s, reports of polar bears (Ursus maritimus) using tools (i.e., pieces of ice or stones) to kill walruses (Odobenus rosmarus) have been passed on verbally to explorers and naturalists by their Inuit guides, based on local traditional ecological knowledge (TEK) as well as accounts of direct observations or interpretations of tracks in the snow made by the Inuit hunters who reported them. To assess the possibility that polar bears may occasionally use tools to hunt walruses in the wild, we summarize 1) observations described to early explorers and naturalists by Inuit hunters about polar bears using tools, 2) more recent documentation in the literature from Inuit hunters and scientists, and 3) recent observations of a polar bear in a zoo spontaneously using tools to access a novel food source. These observations and previously published experiments on brown bears (Ursus arctos) confirm that, in captivity, polar and brown bears are both capable of conceptualizing the use of a tool to obtain a food source that would otherwise not be accessible. Based on the information from all our sources, this may occasionally also have been the case in the wild. We suggest that possible tool use by polar bears in the wild is infrequent and mainly limited to hunting walruses because of their large size, difficulty to kill, and their possession of potentially lethal weapons for both their own defense and the direct attack of a predator.
Highlights
Tool use in the animal kingdom has been the subject of considerable interest for decades and has been documented in a wide variety of species ranging from insects to mammals
Using our own cumulative and extensive scientific knowledge of the behavior and ecology of both polar bears and walruses, the history of Arctic exploration, and traditional ecological knowledge (TEK) publications that include aspects of hunting of polar bears and marine mammals by Inuit in the marine ecosystem, we focused on 1) books and reports written by explorers or scientists who had been active in the Arctic from the 19th century through the first half of the 20th century, especially those who had remained in areas frequented by both polar bears and walruses for extended periods of TOOL USE BY POLAR BEARS HUNTING WALRUSES
It was not possible to assess the uniqueness of some observations so we tabulated all reports separately under the following categories: secondhand accounts from non-attributed TEK sources, firsthand accounts from Inuit hunters, and direct observations reported by those who published them
Summary
Tool use in the animal kingdom has been the subject of considerable interest for decades and has been documented in a wide variety of species ranging from insects to mammals (see reviews by Alcock, 1972; St Amant and Horton, 2008; Bentley-Condit and Smith, 2010; Shumaker et al, 2011). In their extensive review, Bentley-Condit and Smith (2010) created 10 separate categories within which to classify documentation of tool use, including whether a particular observation was anecdotal, only seen in captivity, or only observed in one subject. To some degree, it likely reflects a general lack of experimental studies of the abilities of captive species of bears to solve different kinds of problems in captive situations
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
