Catfish are large, scaled fish that live in rivers all over the world, from Cambodia to Texas. Catfish are distinctive for their facial spines, which often inject poison when they puncture skin. They are also popular sport fish because of their size, particularly Ictalurus furcatus, the blue catfish of the Mississippi river. Blue catfish, like many other species of catfish, eat small invertebrates and, on occasion, other fish. Catfish are edible and have been incorporated into regional cuisines wherever they are found.
Anacondas are native to South America and live in the ecological zone that surrounds the twisting and tropical Amazon river. Anacondas, which can grow to more than 20 feet in length, often swim in the river to stay cool and hunt for prey. These snakes kill by wrapping themselves around their prey and constricting until the unfortunate creature suffocates; the anaconda then unhinges its jaws and swallows its meal whole. Anacondas are not venomous but do possess a set of sharp teeth.
These large and powerful creatures live in tropical African rivers, including Egypt's Nile river. Hippopotamuses are herbivorous mammals that use the river to protect themselves from sunburn and to regulate their temperature. At night, they depart the river to eat massive amounts of plant material. Hippopotamuses are extremely dangerous creatures, and have been known to kill humans with their enormous teeth and mouths.
Dragonflies are highly adapted insects that spend their entire lives in aquatic ecosystems, normally rivers. They begin life as nymphs, swimming around the river searching for food and growing steadily. After some time, which can be years, the nymph grows wings and takes flight. Dragonflies spend their time hunting other insects and searching for mates. There are several thousand species of dragonfly, each with unique coloration.
Many species of turtle live in and around freshwater river systems. The giant Amazon river turtle spends its entire life in the Amazon river and is one of the largest river turtles anywhere. These turtles eat plant material that falls into the river, particularly fruit and nuts. Females leave the river only once during the year to lay a large clutch of eggs. Amazon river turtles have been popular poaching targets throughout the years, but are not endangered.
