Jamieson, Fausset and Brown on 1 Samuel 17:34-36

34-36. a lion, and a bear--There were two different rencontres, for those animals prowl alone. The bear must have been a Syrian bear, which is believed to be a distinct species, or perhaps a variety, of the brown bear. The beard applies to the lion alone. Those feats seem to have been performed with no weapons more effective than the rude staves and stones of the field, or his shepherd's crook.