Characins, such as the piranha species, are prey for the Giant Otter, but these aggressive fish may also pose a danger to humans.

Date: 2015-10-07; view: 577.

More than one-third of all species in the world live in the Amazon Rainforest, a giant tropical forest and river basin with an area that stretches more than 5 400 000 square kilometres (2 080 000 sq mi). It is the richest tropical forest in the world in terms of biodiversity. There are over 2 100 species of fish currently recognized in the Amazon Basin, with more being discovered every year.

Along with the Orinoco, the Amazon is one of the main habitats of the boto, also known as the Amazon River Dolphin (Inia geoffrensis). It is the largest species of river dolphin, and it can grow to lengths of up to 2.6 metres (8.5 ft). ). The color of its skin changes with age. It varies from gray when it is young, to pink and white as it matures. The boto is the subject of a very famous legend in Brazil about a dolphin that turns into a man and seduces maidens by the riverside. The tucuxi (Sotalia fluviatilis), also a dolphin species, is found both in the rivers of the Amazon Basin and in the coastal waters of South America.

The Amazonian Manatee also known as “seacow” is found in the northern Amazon River Basin and its tributaries. It is a mammal and an herbivore.

The Amazon and its tributaries are the main habitat of the Giant Otter (Pteronura brasiliensis). The giant otter is a member of the weasel family and is the largest of its kind. Because of habitat destruction and hunting its population has dramatically decreased.

Also present in large numbers is the notorious piranha, a carnivorous fish which congregates in large schools, and may attack livestock and even humans. There are approximately from 30 to 60 species of piranha. However, only a few of its species are known to attack humans, most notably Pygocentrus nattereri, the Red-bellied Piranha.

The bull shark (Carcharhinus leucas) has been reported 4 000 kilometres (2 500 mi) up the Amazon River at Iquitos in Peru. The arapaima, known in Brazil as the pirarucu (Arapaima gigas), is a South American tropical freshwater fish. It is one of the largest freshwater fish in the world, reportedly with a maximum length in excess of 4.5 metres (15 ft) and weight up to 200 kilograms (440 lb). Another Amazonian freshwater fish is the arowana (or aruanã in Portuguese), such as the Silver arowana (Osteoglossum bicirrhosum), which is also a predator and very similar to the arapaima, but only reaches a length of maximum 120 centimetres (47 in). The anaconda snake is found in shallow waters in the Amazon Basin. One of the world's largest species of snake, the anaconda spends most of its time in the water, with just its nostrils above the surface. In addition to the thousands of species of fish, the river supports crabs, algae, and turtles.

The Black caiman (Melanosuchus niger) is a crocodilian. It is a carnivorous reptile that lives along slow-moving rivers and lakes, in the seasonally flooded savannas of the Amazon basin. The black caiman has a bony ridge over brown eyes, and black, scaly skin. The skin coloration helps with camouflage during its nocturnal hunts. The Black caiman is one of the largest reptiles. It is the largest predator in the Amazon basin and possibly the largest member of the Alligator family. Most adult black caimans are 3 to 4.26 meters (10 – 14 feet), with old males rarely growing larger than 5 meters (16.5 ft). Immature specimens eat crustaceans and insects but quickly graduate to eating fish, including piranhas, catfish, and perch, which remain the primary food source for all Black caiman. Various prey will be taken by opportunity, includes turtles, birds and mammals, the latter two mainly when they come to drink at the river banks. Larger specimens can take tapirs, anacondas, deer and capybara.

Wildlife of the …

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Mammals

Exercise 13. Read the following texts “Mouth” and “Tidal Bore” (then the students are divided into two groups). The first group prepares diagram of the text “Mouth” for the second group to fill it in, the second group prepares the diagram of the text “Tidal Bore” for the first group to fill it in. Compare the filled diagrams with the originals and discuss the differences: