Mink ("Mustela vison"), striped skunk ("Mephitis mephitis"), red fox ("Vulpes fulva"), and coyote ("Canis latrans") also hunt within the estuary. Beaver ("Castor canadensis") and muskrat ("Ondatra zibethicus") are occasionally seen swimming in tidal creeks. A few harbor seal ("Phoca vitulina") haul-out sites exist on the Brave Boat harbor, Lower Wells, Mousam River and Goose Rocks divisions. Peak use occurs during the winter, but individuals are observed throughout the year. The Lower Wells haul-out site receives the most use, with peak counts of 30 seals. During the winter months harp seals ("Pagophilus groenlandicus"), and occasionally hooded seals ("Cystophora cristata") and grey seals ("Halichoerus grypus"), can be found basking on refuge salt marshes and in offshore waters. Seal strandings are a common occurrence, and are reported to marine animal rescue agencies.