Learn 5 Unusual Facts About Dolphins. Of all marine animals, none seem to charm and fascinate people as much as dolphins, which are among the most intelligent animals on earth. Dolphins most often live in groups called pods and operate socially, even playing with each other simply for fun. Dolphins can even be friendly towards other species, and there have been numerous reports of them helping people in need. Dolphins cannot stay under water for very long and must surface for air after 10-20 minutes. The noises, clicks, and whistles that individual dolphins make can be used to identify and distinguish them, because they are unique.