Strangers in a Strange Aquatic Land?

The biotic nature of some large freshwater animals that we usually associate with marine habitats is the main topic of this chapter, with most but not all of these creatures typically inhabiting tropical and subtropical habitats. These include stingrays, sharks, manatees, dolphins, and seals. Recent aquatic invaders to continents—like zebra mussels and snakeheads—are also described.