You wouldn't think so, but there are thousands of dolphins swimming in the southern North Sea. There used to be a lot of bottlenose dolphins as well, but now you see white-beaked dolphins more often. Every once in awhile, a short-beaked common dolphin or a white-sided dolphin is spotted. Even more rare are Risso's dolphins, striped dolphins, orcas or pilot whales. Beaked whales form a separate group and include the bottlenose whale. These are ocean animals, which occasionally swim into the North Sea.