The giant river turtle is one of the largest freshwater turtles in the world. They are also known as the arrau turtle, the South American river turtle, giant South American turtle, giant Amazon River turtle, Arrau sideneck turtle or simply the Arrau. Like sea turtles, these turtles are migratory, traveling hundreds of miles up and down rivers each year; each will dig its single nest for the season in a sandbank. After nightfall, they emerge and crawl somewhat cautiously to the highest ground, advancing haltingly in overlapping swarms of movement, ever ready to retreat tumultuously into the safety of the river. Hundreds of turtles can be seen nesting and crawling in the moonlight, scraping the sand, digging body pits and nesting chambers and spraying sand.
The giant river turtle is one of the largest freshwater turtles in the world. They are also known as the arrau turtle, the South American river turtle, giant South American turtle, giant Amazon River turtle, Arrau sideneck turtle or simply the Arrau. Like sea turtles, these turtles are migratory, travelling hundreds of miles up and down rivers each year; each will dig its single nest for the season in a sandbank. After nightfall, they emerge and crawl somewhat cautiously to the highest ground, advancing haltingly in overlapping swarms of movement, ever ready to retreat tumultuously into the safety of the river. Hundreds of turtles can be seen nesting and crawling in the moonlight, scraping the sand, digging body pits and nesting chambers and spraying sand.
Sea Turtle Versus Freshwater Turtle
Did you know the difference between a sea turtle and a freshwater turtle?
The Giant Leatherback is a sea turtle while the Giant River Turtle is a freshwater turtle. Further, sea turtles are larger in size compared to terrapins and tortoises. Their feet look like flippers and they cannot retract their head and flippers into the shell. Besides, sea turtles are unable to lift their body for locomotion. Thus, they can only crawl on the beach. On the other hand, freshwater turtles are also known as terrapins. There are hard-shelled and soft-shell turtles. Freshwater turtles are typically found in rivers, ponds, and lakes. Unlike sea turtles, terrapins possess webbed feet and they can retract their head and feet into the shell. They are also able to lift their body and walk on nesting sandbanks.
Features Of The Giant River Turtle
- Colour – Giant river turtles are brown, grey or olive-green, but the exact colour varies depending on the algae growing on the carapace.
- Shape – In addition to an overall smaller size, males can be recognized by their longer tail and straighter carapace than the females.
- Weight & Length – They can reach up to 90 kg (200 lb) in weight and the carapace length is up to 1.07 m (3.5 ft). Most individuals are considerably smaller with the average adult female having a carapace length of 64–71 cm (2.1–2.3 ft) and the average adult male 40–50 cm (1.3–1.6 ft).
Giant River Turtle | By Wilfredor – Own work, CC0, https://commons.wikimedia.org/w/index.php?curid=22945322
Scientific Classifications Of The Giant River Turtle
Giant River Turtle – Podocnemis expansa [Scientific name]
- Kingdom: Animalia
- Phylum: Chordata
- Class: Reptilia
- Order: Testudines
- Suborder: Pleurodira
- Family: Podocnemididae
- Genus: Podocnemis
- Species: P. expansa
Habitat Of The Giant River Turtle
They inhabit deep rivers, ponds, freshwater lagoons and flooded forest in white-, black- and clear-water. These turtles can be found in the Amazon, Orinoco and Essequibo basins in Brazil, Bolivia, Peru, Ecuador, Colombia, Venezuela and Guyana. On occasion, typically after floods, individual turtles turn up in Trinidad.
Diet Of The Giant River Turtle
Giant river turtles feed almost entirely on plant material such as fruits, seeds, leaves and algae, but may also take freshwater sponges, eggs and carcasses of dead animals. Captives have been recorded feeding on meat. Juveniles feed on fish and plant material.
Reproduction Of The Giant River Turtle
When nearing the breeding season, giant river turtles migrate to certain sites where the eggs are laid. In some locations nesting occurs in large groups on beaches, which reduces the risk posed by predators. Some beaches have as many as 500 nesting females. Mating occurs in the water. During and just before the nesting season the species frequently basks, typically in groups. It is suspected that the additional heat accelerates the ovulation in the females. At other times the species is generally not found on land.
Eggs: The female lays an average of 75–123 eggs (average varies depending on region), which are placed during the night in a 60–80 cm (2.0–2.6 ft) deep nest that is dug on the beach. The eggs are laid during the low water season and hatch as the water starts to rise. If it rises too fast or too early, the nest is flooded and the young die within the eggs. As long as nests are not dug up by predators, the hatching success rate is usually high, averaging at 83%. The eggs hatch after about 50 days and the sex of the young depends on the nest temperature (females at higher temperatures, males at lower).
Hatchlings: When hatching, the young are around 5 cm (2 in) long and dart directly for the water, but they emerge to the attentions of many predators so that only about five percent ever reach the adult feeding grounds. Also, when hatching the females emit sounds which attract the young; they stay together for a period in the flooded forests.
Five Facts About The Giant River Turtle
- When on land, it is usually very shy and retreats to the water at the slightest hint of danger. Vocalizations appear to play an important role in the social life of this turtle.
- They can reach an age of 20 years or more in the wild, and captives have lived for at least 25 years. Based on certain scientific models it has been estimated that the largest individuals perhaps are as old as 80 years.
- The giant river turtles are the largest of the side-neck turtles (Pleurodira).
- The species primarily feeds on plant material and typically nests in large groups on beaches. They are mainly active in the day.
- Due to hunting of adults, collecting of their eggs, pollution, habitat loss, and dams, the giant river turtle is seriously threatened.
Giant River Turtles In Guyana
Giant river turtles (Podocnemis expansa) are found in rivers, lakes and ponds in the Iwokrama Forest and the Rupununi of Guyana. Females and males look similar and their large flattened carapace (shell) can measure up to a metre in length. Since 2008, Iwokrama and community members of North Rupununi District Development Board (NRDDB) have been monitoring the river turtles in the Rupununi area and hope to be able to monitor and sustainably manage this important animal.
Article References:
- https://www.aqua.org/Experience/Animal-Index/giant-south-american-river-turtle
- https://en.wikipedia.org/wiki/Arrau_turtle
- https://www.stabroeknews.com/2011/01/16/features/giant-river-turtle/
- http://www.reptilesmagazine.com/Wild-Turtles-And-Tortoises/The-Giant-River-Turtles/
- https://www.mybis.gov.my/art/250
- Main Image: Giant River Turtle | Whaldener Endo / CC BY-SA (https://creativecommons.org/licenses/by-sa/4.0)
