--- title: Great rivers and wetlands: Nile crocodiles, hippos, giant catfish and the Pantanal — a lesson of Mova's school · trees and pragmatics description: «Great rivers and wetlands: Nile crocodiles, hippos, giant catfish and the Pantanal», a lesson of the biology course of Mova's primary school, sentence by sentence with dependency trees and pragmatics. It begins: A great river is a long road of water through the land, and wherever it spreads into sw --- [Mova](https://md.mova.elamur.ai/free/en/) · [this page in HTML](https://mova.elamur.ai/free/en/corpora/school/biology/184-great-rivers-and-wetlands-nile-crocodiles-hippos-giant-catfish-and-the-pantanal/) [home](https://md.mova.elamur.ai/free/en/) / [corpora](https://md.mova.elamur.ai/free/en/corpora/) / [school](https://md.mova.elamur.ai/free/en/corpora/school/) / [Biology](https://md.mova.elamur.ai/free/en/corpora/school/biology/) / Great rivers and wetlands: Nile crocod… # Great rivers and wetlands: Nile crocodiles, hippos, giant catfish and the Pantanal Lesson 184 of the biology course of Mova's primary school: 15 sentences, each with its syntax tree and pragmatics. The lessons are written for Mova, and their agreed trees are part of Mova corpus 0.4 (CC BY-SA 4.0). How Mova does on its tests: [the lesson at school](https://md.mova.elamur.ai/free/en/school-run/biology/184-great-rivers-and-wetlands-nile-crocodiles-hippos-giant-catfish-and-the-pantanal/). - [0](https://md.mova.elamur.ai/free/en/corpora/school/biology/184-great-rivers-and-wetlands-nile-crocodiles-hippos-giant-catfish-and-the-pantanal/0/) — A great river is a long road of water through the land, and wherever it spreads into swamps, lakes and floods, it becomes a wetland packed with life, from giant fish to pink flamingos. - [1](https://md.mova.elamur.ai/free/en/corpora/school/biology/184-great-rivers-and-wetlands-nile-crocodiles-hippos-giant-catfish-and-the-pantanal/1/) — Animals plan their lives around the water: wildebeest must cross rivers to reach new grass, and Nile crocodiles wait at exactly those crossings, like someone waiting at the school gate who knows when the bell rings. - [2](https://md.mova.elamur.ai/free/en/corpora/school/biology/184-great-rivers-and-wetlands-nile-crocodiles-hippos-giant-catfish-and-the-pantanal/2/) — Rivers hold some of the biggest freshwater fish on Earth, dolphins that find food in muddy water by echoes, and in Brazil's Pantanal, jaguars that hunt caimans along the banks. - [3](https://md.mova.elamur.ai/free/en/corpora/school/biology/184-great-rivers-and-wetlands-nile-crocodiles-hippos-giant-catfish-and-the-pantanal/3/) — Water even moves across a desert: in Botswana the Okavango river floods in the middle of the dry season, because rain that fell far away takes months to arrive. - [4](https://md.mova.elamur.ai/free/en/corpora/school/biology/184-great-rivers-and-wetlands-nile-crocodiles-hippos-giant-catfish-and-the-pantanal/4/) — Nile crocodiles wait at places where wildebeest and zebras cross rivers to reach new grass, and after a big meal a crocodile can go many months without eating. - [5](https://md.mova.elamur.ai/free/en/corpora/school/biology/184-great-rivers-and-wetlands-nile-crocodiles-hippos-giant-catfish-and-the-pantanal/5/) — Hippos yawn widely to show their huge teeth as a warning; they are very territorial and are often said to kill more people in Africa than lions do. - [6](https://md.mova.elamur.ai/free/en/corpora/school/biology/184-great-rivers-and-wetlands-nile-crocodiles-hippos-giant-catfish-and-the-pantanal/6/) — The Mekong giant catfish is one of the biggest freshwater fish, as heavy as a bear, has no teeth as an adult, eats algae and plants, and is now very rare because of dams and fishing. - [7](https://md.mova.elamur.ai/free/en/corpora/school/biology/184-great-rivers-and-wetlands-nile-crocodiles-hippos-giant-catfish-and-the-pantanal/7/) — The Ganges river dolphin is almost blind and finds food by echolocation (making clicks and listening for their echoes), because the muddy river water makes eyes nearly useless, and it swims on its side to search the bottom. - [8](https://md.mova.elamur.ai/free/en/corpora/school/biology/184-great-rivers-and-wetlands-nile-crocodiles-hippos-giant-catfish-and-the-pantanal/8/) — In 2022 a giant freshwater stingray of about three hundred kilograms was caught in the Mekong River in Cambodia; it was measured, tagged and released, and was reported as the biggest freshwater fish ever recorded. - [9](https://md.mova.elamur.ai/free/en/corpora/school/biology/184-great-rivers-and-wetlands-nile-crocodiles-hippos-giant-catfish-and-the-pantanal/9/) — The Pantanal in Brazil is the world's biggest tropical wetland, where jaguars hunt caimans (cousins of crocodiles) and capybaras (giant rodents) and big animals are easier to see than in the rainforest. - [10](https://md.mova.elamur.ai/free/en/corpora/school/biology/184-great-rivers-and-wetlands-nile-crocodiles-hippos-giant-catfish-and-the-pantanal/10/) — The shoebill is a huge bird with a beak like a shoe that stands still for hours waiting for lungfish to come up to breathe, and it clatters its beak loudly. - [11](https://md.mova.elamur.ai/free/en/corpora/school/biology/184-great-rivers-and-wetlands-nile-crocodiles-hippos-giant-catfish-and-the-pantanal/11/) — Beavers build dams that make ponds where many other animals live, and one beaver dam in Canada is so big it can be seen in pictures taken from space. - [12](https://md.mova.elamur.ai/free/en/corpora/school/biology/184-great-rivers-and-wetlands-nile-crocodiles-hippos-giant-catfish-and-the-pantanal/12/) — Salmon swim upstream from the sea to the river where they hatched, finding it by smell, and leftovers from bears catching salmon help feed forest trees. - [13](https://md.mova.elamur.ai/free/en/corpora/school/biology/184-great-rivers-and-wetlands-nile-crocodiles-hippos-giant-catfish-and-the-pantanal/13/) — The Okavango river floods a desert in the middle of the dry season, because rain from far away takes months to flow down to the delta, and the flood feeds elephants, lions and birds. - [14](https://md.mova.elamur.ai/free/en/corpora/school/biology/184-great-rivers-and-wetlands-nile-crocodiles-hippos-giant-catfish-and-the-pantanal/14/) — Flamingos get their pink colour from pink chemicals in the tiny algae and shrimps they eat, so zoo flamingos are given special food to stay pink. - ← previous: [Mountains of the world: snow leopards, high-flying geese, condors and Everest spiders](https://md.mova.elamur.ai/free/en/corpora/school/biology/183-mountains-of-the-world-snow-leopards-high-flying-geese-condors-and-everest-spiders/) - next →: [Record-breakers: the fastest and the slowest](https://md.mova.elamur.ai/free/en/corpora/school/biology/185-record-breakers-the-fastest-and-the-slowest/) - ↑ back to [Biology](https://md.mova.elamur.ai/free/en/corpora/school/biology/)