South American river turtles fulfill an important ecological role spreading seed through feces, providing food for predatory species and acting as "cleaners" of turtle habitats by consuming dead plant material. Of the 300 turtle species worldwide, 42 occur in South America including 30 side-necked turtles, which predominantly occur in river systems.
One Killer Turtle
In Spanish, the matamata's name means, "I kill, I kill." It is an apt name considering his hunting practices. Primarily a carnivore, he will sit in the mud at the bottom of a pond or slow-moving stream and wait for his prey to swim by. When the opportunity presents itself, the matamata strikes out and sucks, much like a vacuum, collecting water and prey into his mouth. He expels the water and swallows his prey whole. Although the matamata spends nearly all of his life in the water, he is a lousy swimmer, preferring instead to walk along the bottom of his watery habitat. His snout, a long tube, acts like a snorkel, minimizing his surface time. His most prominent feature is his sheer ugliness, saving him from the soup pot of even the most dedicated turtle-eating people.
The Gentle Giants
The arrau turtle, or South American river turtle, grows larger than any other side-necked turtle. Rather than retract his head directly back into his shell for protection, a side-necked turtle must fold it to the side, leaving part of the head exposed. Growing up to 100 pounds, female arrau turtles will gather on beaches and sand bars to nest, sometimes in groups as large as 500 turtles. Despite the arrau's large size, he is an herbivore, feeding on flowers, roots, fruits and aquatic plants. The arrau prefers large rivers such as the Amazon and Orinoco, or tributaries and lagoons under dense forest. In addition to humans, the arrau turtle is hunted by jaguars and crocodiles.
The Yellow-Spotted Turtle
Among the larger of South America's river turtles, this striking-looking turtle is known for the yellow spots on his head. Unlike many other animal species, female yellow-spotted turtles can weigh twice as much as males. More omnivorous in nature than the arrau turtle, the yellow-spotted turtle adds fish and small invertebrates into his diet of plants and fruit. Primarily aquatic, he only leaves the water to warm himself on a hot rock or a sandy beach.
A Skunk of a Turtle
The gibba turtle, also known as a musk turtle, is an unsociable fellow who lives in shallow marshes, ponds and streams. Shy in nature and primarily nocturnal, he will emit a foul-smelling aroma if captured. He also is inclined to bite. Primarily aquatic, the gibba can remain submerged for prolonged periods of time, and feeds on plants, tadpoles and insect larvae.