Chelus fimbriatusMata Mata

Geographic Range

Chelus fimbriatus ranges from the Amazon and Orinoco river systems in Venezuela and Colombia, south to the Tocatina, Araguala, and Xingu rivers of Brazil and Bolivia. Its range also extends west to Equador and Peru, and east into the eastern Amazon river basin. It also occurs on the island of Trinidad.

Chelus fimbriatus has been reportedly introduced into the drainage canals of southeast Florida, though a self-sustaining breeding population has not been confirmed. This introduction may be due to carelesness associated with the pet trade. Possible detrimental effects on Florida's native habitat have not yet been noted or investigated (Ernst and Barbour 1989, Espenshade 1990, USGS Biological Research Division 1999).


Chelus fimbriatus prefers shallow, slow moving, turbid bodies of water such as rivers, blackwater streams, swamps, and marshes. The brackish waters of the lower Amazon basin are also inhabited. Soft muddy bottoms are prefered. Chelus fimbriatus is totally aquatic and rarely moves over land (Ernst and Barbour 1989, Espenshade 1990).

  • Aquatic Biomes
  • lakes and ponds
  • rivers and streams

Physical Description

Chelus fimbriatus is almost surreal in appearance, and at first glance may resemble a pile of debris. Younger animals are salmon pink to reddish-brown in coloration with black to green mottling. As C. fimbriatus matures, the pinkish hues are replaced by faded yellow, washed out browns, oranges, and greys. The carapace has three lengthwise knobby keels. Algae may cover much of the carapace causing the animal to virtually disappear into its surroundings. A fairly large turtle, C. fimbriatus may reach a carapace length of nearly 45 cm. The head is broadly triangular with large lateral flaps of skin. Several hypotheses have been proposed on the possible functions of these flaps. It is known that the flaps have nerves that respond to various stimuli, including motion in the surrounding water. Tubercles on the head near the corners of the mouth and neck, and barbels on the chin, also are reported to have sensory nerves, possibly used in detecting water vibrations and other external stimuli. The snout has evolved into a long protuberance used as a snorkel, minimizing the turtle's movement as only the tip of the snout emerges form the water during respiration. The back of the eyes are lined with a tapetum lucidum, a visual adaptation which reflects light. This is seen also in other nocturnal reptiles. Despite this, C.fimbriatus has extremely poor eyesight. This turtle can sense auditory stimuli obtained through a well developed tympanum on both sides of the head. Chelus fimbriatus is a poor swimmer with legs adapted for walking on the bottom of their muddy habitats. Hatchlings and juveniles can swim awkwardly. Adults rarely leave the bottom of shallow pools and streams. Chelus fimbriatus is only sexually dimorphic after reaching maturity. Males have a concave plastron and rather long, thick tails; females have a flatter plastron and smaller tails. With tail extended, the male's vent (anal opening) is beyond the posterior edge of the carapace; the female's vent is under the edge of the carapace (Alderton 1988, Ernst and Barbour 1989, Kirkpatrick 1992).

  • Sexual Dimorphism
  • sexes shaped differently
  • Range length
    45 (high) cm
    17.72 (high) in


Prior to mating, male Chelus fimbriatus will repetitively extend the head toward the female while opening and closing the mouth.

Movement of the lateral flaps on the head has been observed during this courtship ritual, as well as a hyperextension of the legs from the shell.

Eggs are laid from October through December in the upper Amazon regions. Unlike most Amazonian turtles, which nest in open sandy places, mata matas may excavate their nests in decaying vegetation at the forest edge The eggs are about 3.5 centimeters in diameter and are almost spherical. One clutch may contain 12 to 28 eggs which have a relatively long incubation period. Incubation periods of around 200 days incubated at 28 to 29 degrees Celsius have been noted for captive individuals. (Ernst and Barbour 1989, Espenshade 1990).

  • Breeding interval
    Breeding occurs once yearly.
  • Breeding season
    Breeding and egg-laying occur from October through December.
  • Range number of offspring
    12 to 28
  • Average gestation period
    200 days

Young mata matas hatch from their eggs and emerge from the nest on their own, there is no parental care.

  • Parental Investment
  • no parental involvement


There is little information on the longevity of these animals in the wild. In captivity they may live up to 15 years.

  • Typical lifespan
    Status: captivity
    15 (high) years


Mata matas rarely bask and spend most of their time under water, with the exception of females hauling out onto land to nest. Because of their relatively weak limbs, C. fimbriatus prowl the muddy bottoms of their habitat, and seldom, if ever, swim. This is a solitary species that rarely interacts with members of its own species except when breeding. They are active during the day and night.

Physical characteristics of this turtle correlate closely to its behavioral characteristics. Resembling a pile of debris and using slow and deliberate motions, mata matas blend easily into the surrounding habitat (Ernst and Barbour 1989, Espenshade 1990).

Communication and Perception

Mata matas have poor vision, but seem to have excellent tactile and auditory senses. The complex folds of skin on their bodies may hold sensory nerves that help to detect motion (see Physical description).

Male mating displays involve touch and physical displays.

Food Habits

Chelus fimbriatus is primarily carnivorous. Its diet consists mainly of fish, and aquatic invertebrates. The mandibles are not attached medially, and the relatively weak jaws are unsuited for seizing and chewing prey. Chelus fimbriatus must rely on well developed neck musculature and the hyoid apparatus in the throat. When a potential prey item comes within range of the turtle, the turtle will strike out and open its mouth. Large amounts of water, and the prey item, are sucked in by the low pressure that is created. The mouth is then closed and excess water is expelled. The prey item is swallowed whole. While foraging, C. fimbriatus may trawl the water making lateral movements with its neck and head; at other times the turtles remain still and simply wait for fish or invertebrates to approach. Chelus fimbriatus has also been observed to herd fish into a restricted area and confine them before feeding. The cryptic appearance of C. fimbriatus contributes to its efficiency as a predator; the various neck fringes and algae growth may entice unwary fish to approach in search of food-- and before the prey are even aware of the turtle's presence, it is already too late to escape (Alderton 1988, Ernst and Barbour 1989, Espenshade 1990, Kirkpatrick 1992).

  • Animal Foods
  • fish
  • aquatic or marine worms


Mata matas avoid predation by being cryptic and through their large size and thick carapace.

  • Anti-predator Adaptations
  • cryptic

Ecosystem Roles

Mata matas are important predators of small fish and aquatic invertebrates in the ecosystems in which they live.

Economic Importance for Humans: Positive

Chelus fimbriatus is sometimes collected and sold in the pet trade, and is also captured and eaten by people, though its odd and unappetizing appearance may sometimes save it from the soup pot. As with all organisms, mata matas play a role in the functioning of their local ecosystem.

Economic Importance for Humans: Negative

If Chelus fimbriatus became established in southeast Florida, research would be needed to determine the impact, if any, it might have on native fauna.

Conservation Status

Chelus fimbriatus has no special status. However with rapid destruction of its native habitat, this may not hold true in the future.

Other Comments


Chelus fimbriatus is a member of the Suborder Pleurodira; the side-necked turtles, and is in the family Chelidae ("snake-necked turtles"). Pleurodira bend their neck to the side when pulling it under the edge of the carapace rather than retracting it directly inward, as seen in the Cryptodira, or hidden-necked turtles. Chelus fimbriatus is the sole species in its genus. Although variation in skin and shell color, and in shell shape has been observed, no subspecies are yet identified. The common name "matamata" is said to have the meaning "I kill" in one of the South American native languages. The name Chelus fimbriatus was given by Mertens and Muller in 1934, meaning "fringed turtle".


Benjamin Davidson (author), Michigan State University, James Harding (editor), Michigan State University.



living in the southern part of the New World. In other words, Central and South America.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.


an animal that mainly eats meat


uses smells or other chemicals to communicate


having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

  1. active during the day, 2. lasting for one day.

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature


union of egg and spermatozoan


A substance that provides both nutrients and energy to a living thing.


mainly lives in water that is not salty.


having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

internal fertilization

fertilization takes place within the female's body


offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).


marshes are wetland areas often dominated by grasses and reeds.


having the capacity to move from one place to another.


specialized for swimming

native range

the area in which the animal is naturally found, the region in which it is endemic.


active during the night


reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

pet trade

the business of buying and selling animals for people to keep in their homes as pets.


an animal that mainly eats fish


having more than one female as a mate at one time

seasonal breeding

breeding is confined to a particular season


remains in the same area


reproduction that includes combining the genetic contribution of two individuals, a male and a female


lives alone


a wetland area that may be permanently or intermittently covered in water, often dominated by woody vegetation.


uses touch to communicate


the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.


movements of a hard surface that are produced by animals as signals to others


uses sight to communicate


Alderton, .. 1988. Turtles and Tortoises of the World. New York: Facts-On-File Pub..

Ernst, .., .. Barbour. 1989. Turtles of the World. Washington, D.C., and London: Smithsonian Institution Press.

Espenshade, .. May 1990. Matamata, Chelus fimbriatus. Tortuga Gazette, 26:(5): 3-5.

Kirkpatrick, .. 1992. The Matamata. Reptile and Amphibian Magazine, Sept/Oct, 1992: 34-39.