The seal has always played a prominent role in the mythologies of northern people, and selkies are spirits in the mythology of people from the Shetland and Orkney Islands. They appear as seals most of the time, but are also capable of changing into human form. The Celts believed that although fallen angels looked like people on land, they looked like seals in water. Seals are playful animals. If you dream of a seal, it's a sign that you are taking life far too seriously and should adopt a more playful attitude.