Otters

The otters (Mustelidae; Lutrinae) provide a unique look into the evolution of marine living by mammals. This is because most extant marine mammals have been so highly modified by long periods of selection for life in the sea that they bare little resemblance to their terrestrial ancestors. Marine otters, by contrast, are recent expatriates from terrestrial and freshwater habitats, and some species still live in both environments. Contrasts within this group, and among the otters, terrestrial mammals, and the more highly adapted pinnipeds and cetaceans potentially offer deep insight into mammalian adaptations to life in the sea. Among the marine mammals, sea otters also provide the clearest understanding of predation and ocean ecosystem function. This is due in part to serendipitous opportunities provided by history and in part by the relative ease with which shallow coastal systems where sea otters live can be observed and studied. These two qualities of the otters are what make them interesting to marine mammalogy. Thus, our contribution to this volume on the marine mammals is built around these themes.