According to Rudolf Simek, "the squirrel probably only represents an embellishing detail to the mythological picture of the world-ash in Grímnismál".[9] Hilda Ellis Davidson, describing the world tree, states the squirrel is said to gnaw at it—furthering a continual destruction and re-growth cycle, and posits the tree symbolizes ever-changing existence.[10] John Lindow points out that Yggdrasil is described as rotting on one side and as being chewed on by four harts and Níðhöggr, and that, according to the account in Gylfaginning, it also bears verbal hostility in the fauna it supports.