This large species is similar to the American crocodile. The body is made up of scales (scutes) that vary in shape and strength. Orinoco crocodiles can be identified by the arrangement of dorsal (back) armor with six prominent scales on the back of the neck. Osteoderms (bony deposits within each scale) are rough in texture and are often different in color. Orinoco crocodiles have no osteoderms on their light colored belly, Another identifying feature of the Orinoco crocodile is the narrow snout which slopes upward near the tip. The nostrils are set at the end to allow breathing while mostly submerged. The tongue is wide and attached to the bottom of the mouth and does not aid in the capturing of prey. Their body color varies from gray-green, tan, to gray scattered with dark green. The legs are short and strong; the long tail is quite powerful.
Not related to saltwater or migratory eels, this South American fish has an elegantly minimal method of moving through water. This is mostly achieved by a parabolic wave generated through the long ventral fin. The tiny pectoral fins may steer. Most of the body is taken up by electricity generating tissue. An adult may produce a 500-watt charge. The digestive and reproductive organs are confined to a small area just behind the head. Exhibited at New York’s Central Park Zoo more than a century ago, it has long been a popular aquarium display.
Very few of the 180 or so caecilian species are easily exhibited in zoos or aquariums, as most live underground. This South American species is an exception, living in water instead. It has been bred in captivity, including the DWA, giving birth to live young. Confined to parts of the Old and Near World Tropics, caecilians compose one of the three orders of amphibians (the other two being frogs and toads, and salamanders). They are the only living amphibians with scales, but these are hidden beneath their skin.
A resemblance to a pile of rotting leaves serves this reptile well. When unaware small fishes swim too close, they disappear instantly — sucked in by a powerful vacuum created when it opens its jaws. Found in quiet water across a large area of tropical South America, it usually only comes onto land to lay its eggs. It rarely swims, preferring to walk underwater, taking air at the surface through the unique proboscis in front of its tiny eyes.
In the 1960s, vast numbers of the tiny, brightly colored young of this species were sent to the US with shipments of tropical fish, but most did not survive. Since females may exceed 17 inches in shell length, they are not appropriate for most home aquariums. Serious private collectors and zoos have done well with them, and they have bred many times in captivity. While considered vulnerable to extinction, they remain an important resource for Native Americans in parts of their wide South American range.
Though the Silver and Black arowanas of South America, and the Asian and Australian arowanas resemble each other, and share the behavior of brooding their eggs and fry in their mouths, they last shared a common ancestor around 170 million years ago, when the great Southern Continent Gondwana began to split apart. This took place in the Jurassic period, when dinosaurs still thrived. Although Asian arowanas are endangered, South American ones are abundant, and are important both to subsistence fishing and the sustainable aquarium trade.
It appears there are no documented cases of piranhas killing people, but there have been several cases where they have eaten humans that had drowned. In general, these specialized relatives of the tetras are opportunistic scavengers. Of the 50 or so species found in South American Rivers, this one is the most familiar, and is popular in aquariums for its bright colors. If maintained in groups of less than four, piranhas are likely to eventually kill each other. They have been bred many times in captivity.
Rarely longer than five feet, this widespread South American alligator relative is the smallest species of living crocodilians. In contrast to most other crocodilians, it prefers fast moving streams with relatively cool water. Rare in collections before the 1980s, it is now bred in captivity.
Until 2001, when the Giant huntsman spider was discovered in Laos, this enormous tarantula of the Northern South American rainforests was known as the largest spider in the world, and is still the heaviest. The legs may span one foot and they can weigh up to six ounces. While it is certainly capable of eating small birds, their more usual prey is insects, frogs, and lizards. Their venom is comparable to that of a wasp, but they are also capable of damaging human skin with their detachable irritating hairs. Females can live to be 25 years old and males only to six.
Named for a mythical crowned serpent, basilisks are specialized iguana relatives from Central and South America. They are capable of running on their hind legs so quickly that they can cross water without sinking. The ornate crest on the head is actually an extension of the skull. This species is found from Belize to Colombia, and is also now one of the many reptiles that have become feral in Florida.