Notorious for their sharp teeth and voracious appetites, piranhas inhabit several of the major river basins in South America. These omnivorous fish are known for their taste for meat, although attacks on human beings are quite rare, despite breathless accounts from early explorers.
Electra the electric eel (Electrophorus electricus) demonstrates her shocking power at Ford Motor Company’s “Cycle of Production” exhibit at the 1939 New York World’s Fair. Despite their name, electric eels are actually a type of knifefish and are more closely related to catfish than they are to true eels. These unusual fish inhabit waterways in the Amazon and Orinoco basins of South America, where they hunt prey and defend themselves by producing powerful bursts of electricity.
Goliath Bird-Eater Spider
The second largest spider in the world, the goliath bird-eater (Theraphosa blondi), is related to the tarantula. It received its fearsome name after Victorian explorers witnessed one feasting on a hummingbird.
A mata mata (Chelus fimbriatus) is a freshwater turtle that inhabits the Amazon and Orinoco basins in South America. The bizarre turtles are entirely aquatic, although they prefer shallow, stagnant water, where they can easily reach their head out of water to breathe.
Divers work with a model European catfish in the Great Lake at Ostersund in Sweden. Large catfish live in many rivers throughout the world, where they are important scavengers.
Diving Bell Spider
The diving bell spider (Argyroneta aquatica) is the only known spider in the world that lives entirely underwater. Like other arachnids, it must breathe air, but it provides its own supply by forming a bubble, which it holds by hairs on its legs and abdomen. The spiders must occasionally return to the surface to replenish their air supply, although some gas exchange happens across the surface of their bubbles, so they don’t have to come up very often.
Source: National Geographic