The superfamily Musteloidea represents an ecologically and morphologically diverse collection of mammals. Lutrinae, the subfamily within Musteloidea that contains otters, includes 13 extant species across five continents in a variety of (semi-)aquatic/marine environments. Besides elucidating musculature, skeletal structures can provide evidence for behavior and ecology. In this study, we use linear measurements and 2-dimensional geometric morphometric analysis of the three forelimb long-bones (humerus, radius, and ulna) from eight species of extant otters, as well as a number of subspecies, to observe whether unique tool-use behavior of sea otters can be analytically captured and differentiated from other otters.