Mammalia (Mammals)  

The red deer and otter are probably the only two native species of terrestrial mammals in the Outer Hebrides. The other species have been introduced deliberately by man or arrived as a result of his activities. With the exception of pipistrelles, which occur in and around Stornoway, other species of bats have only been recorded as vagrants.
The Hebrides are an important areas for marine mammals; grey and common seals breed on the offshore islands,and a number of cetacean species (whales, dolphins and porpoises) are regularly reported.