The Matamata

by David T. Kirkpatrick, Ph.D

If you are not an ardent turtle-lover, one aquatic turtle tends to look a lot like any other aquatic turtle. Cooters, Painteds and Sliders all begin to blur together after a while. However, there are some true individuals among the various species of turtles. For example, it is very hard for anyone to confuse a Pancake tortoise with any other turtle. Among the small number of truly unique turtles, the Matamata has a distinguished place of honor. Anyone who has ever seen a Matamata will instantly recognize it again.

Although the South American Indian name for this sidenecked turtle, "matamata", means "I kill" {according to Fritz Jurgen Obst in his book" Turtles, Tortoises and Terrapins"}, the Latin name, Chelus fimbriatus, is more descriptive. When describing the turtle in 1743, Schneider chose a Latin name that means "fringed turtle", a description which, although accurate, hardly does it justice. A Matamata's most striking features are its head and neck region. Viewed from above, the head is a broad triangle in shape with a very long, slender snout forming one tip of the triangle. All along the head and long, muscular neck are small, multi-branched tufts or flaps of flesh; these tufts give the turtle its Latin name. These loose tufts drift and sway with any current in the water or movement of the turtle, making the turtle appear as if it was covered with weeds or algae.

A Matamata will grow to be fairly large; turtles with a carapace length of sixteen inches have been captured. In adults the carapace is usually black or brown with some orange color, while the plastron ranges in color from a light yellow to a deeper brown shade. Each individual scute can be fairly rough in appearance, due to the way that the scute grows. Three keels run the length of the carapace; these keels result from the center of each scute raising up to form a knob, with the highest knobs at the back of the carapace. The skin of the Matamata varies from an orange-brown to a grey-brown tone.

All of the physical features of the Matamata aid it in its natural environment. Algae grows on the roughened carapace, causing it to look like an old, encrusted rock. The tufts and fringes along the neck and head may act as a type of camouflage, breaking up the turtle's outline to further disguise it. There is some debate as to whether or not the flaps of skin also serve as sensory mechanisms to allow the turtle to detect nearby movement. Finally, the color of its shell and skin allows the Matamata to blend in to its surroundings.

The use of camouflage and disguise gives the Matamata the chance to take full advantage of its environment in hunting for food. The Matamata inhabits muddy, sometimes stagnant, shallow pools and streams in northern South America, where it ranges as far west as Ecuador and Peru, as far south as Bolivia and central Brazil, and as far north as Colombia and Venezuela. Looking like a pile of rocks or debris, a hungry turtle rests quietly on the bottom, occasionally stretching its long neck up until its snorkel-like nose can be used to take a breath. It will remain almost motionless underwater until a fish comes too close to the Matamata's mouth. At this point, the turtle thrusts out its head and opens its large mouth as wide as possible. This acts like a vacuum cleaner; the prey and a large amount of water are rapidly sucked into the turtle's mouth and throat, which can be stretched out quite a bit. The Matamata snaps its mouth shut, the water is slowly expelled, and the fish is swallowed whole. The prey has to be appropriately sized for the turtle; Matamatas cannot chew very well due to the way their mouths are constructed. Matamatas in the wild may use other methods in addition to the "ambush" approach to capture prey. Occasionally some specimens in captivity have been observed slowly herding fish into a confined area before sucking them into their mouth.

Interestingly, the Matamata resembles a North American turtle, the Alligator Snapper (Macroclemys temmincki), in a number of ways. Each has adopted a unique method of capturing fish: the Alligator Snapper uses a small pink "lure" attached to its tongue to draw prey close enough to bite and swallow, while the Matamata has developed its method of "vacuuming-up" fish. Both species have similar skin and shell coloration and in both the carapace is keeled and roughened, allowing the growth of algae. All of these adaptations serve as disguise for the turtles. Finally, they both inhabit shallow, muddy, slow-moving bodies of water. This environment allows them to "ambush" prey while remaining motionless and camouflaged.

Its unique appearance and large size makes the Matamata a desired zoo specimen and it is well-represented in zoological institutions and private collections worldwide. In addition, its sedentary lifestyle allows it to do well in an enclosure smaller than would be necessary for a more active turtle, making it an even more coveted display animal. Luckily, it generally does reasonably well in captivity, provided that its modest requirements are met, and captive animals have survived for more than a decade and a half.

In captivity the Matamata requires an aquarium with a large surface area but not much depth. Perhaps due to their large size, awkwardness, or the nature of their normal environment, adult Matamatas rarely swim, preferring instead to walk slowly along the bottom. Therefore, the water should be shallow enough that the turtle can stretch its neck up and breathe without moving off of the bottom of the tank, yet deep enough that the animal is fully submersed at all times. The tank does not need to have excess items; Matamatas rarely bask, and so basking logs or rocks are not needed. A land section is also usually not required unless breeding is expected, in which case an area for egg deposition is a necessity.

The feeding of a captive Matamata is relatively straightforward. Most animals require live prey of an appropriate size - the turtle must be able to swallow the fish whole. Bait fish such as minnows are the usual food offered to Matamatas. Although goldfish could be used, some people have reported having problems when turtles are fed exclusively on goldfish. Food fish should probably be kept in a separate aquarium for a few days or longer prior to feeding to the turtle. This allows time to flush out any drugs or chemicals in the fish's system, allows time for it to be fed a high-protein, high-vitamin fish food (analogous to "nutrient-loading" crickets and other insects prior to offering to insectivorous herps), and allows time to observe the fish for signs of disease.

Matamatas have been captive bred. However, captive breeding is still the exception rather than the rule, perhaps due in part to the tendency towards keeping only one animal for exhibition purposes instead of maintaining a captive breeding group. Prior to mating the male turtle will extend its heads towards the female while opening and closing its mouth. After mating, female Matamatas in their natural environment will lay one to two dozen eggs. This generally occurs in the months of October through December, depending on location. These brittle-shelled eggs are almost round and about 3.5 centimeters in diameter. A rather long incubation time of just over 200 days at 28 to 29 degrees C. has been reported for Matamata eggs hatched in captivity.

Hatchling Matamatas are more colorful than adults. The carapace is light brown with a dark stripe running down the center, while the plastron is pink, as are the undersides of the juvenile's limbs and throat. Three narrow black stripes run from the top of the head back along the neck. Usually there are a series of pinkish blotches on scutes along the edge of the carapace, with darker blotches on the more interior scutes. All of these juvenile colorations tend to darken or disappear as the turtle ages, however.

Juvenile Matamatas can be maintained in the same manner as the adults, as long as appropriately sized food animals are presented. Unlike the adults, some juvenile Matamatas will occasionally swim around. Also unlike adults, young Matamatas have been seen to bask on occasion.

The Matamata's unique appearance, large size, and interesting habits make it a desired species of turtle. However, much more information still needs to be gathered about the natural history of this turtle. Captive breeding should also be encouraged, as the Matamata inhabits regions of the world where there are ongoing large-scale alterations in the environment, making the future of the Matamata in the wild uncertain at best.

This article copyright 1992 by David T. Kirkpatrick. Originally published in Reptile & Amphibian Magazine, September/October, 1992, pages 34-39.

Reprinting of this article for non-profit purposes is permitted provided that it is unaltered and appropriate attribution, including copyright information, is included. Please notify the author of any reprinting.