Amazonian Matamata

The Amazonian Matamata is one of the most easily recognizable turtles, with a flat, triangular, and rough shell resembling a dead leaf or piece of bark.

Its color ranges from dark brown to grayish, allowing for perfect camouflage in dark waters. The head is wide, triangular, and depressed, with an elongated tubular snout and numerous skin projections (barbels) on the neck and jaw that mimic aquatic vegetation. The eyes are small and located on top of the head.

The plastron is reduced, cream to brownish in color, leaving the limbs largely visible. In terms of size, an exceptional record was documented in 2006 on the Apure River (Venezuela): a live female measured 50.2 cm in median midline length (MML), 52.6 cm in total shell length, with a total animal length of 83 cm and a weight of 17.7 kg. Although this specimen comes from the distribution range of C. orinocensis, it illustrates the growth potential of the genus, with C. fimbriata commonly reaching 40-45 cm.

The Amazonian Matamata is an exclusively aquatic turtle, extremely slow and disinclined to move on land. It spends the majority of its time immobile on the bottom or floating just below the surface. Its activity is predominantly nocturnal and crepuscular; although it may remain in a hunting position during the day, its movements and prey suction attempts intensify at dusk and dawn.

Solitary, it does not form any structured groups, and individuals only tolerate each other during the breeding season or when concentrated in refuge areas during the dry season.

Its behavior is based on passive mimicry: it rests on mud or beds of dead leaves, sometimes allowing itself to be naturally covered by sedimentation, but without actively seeking to bury itself.

Although it can hold its breath for long periods due to a slow metabolism, it must resurface to breathe atmospheric air. It does so discreetly, taking advantage of darkness to maintain its camouflage.

Its hunting technique is unique: the sudden opening of its tubular mouth creates a powerful vacuum that sucks in water and prey in a fraction of a second.

To repel predators, it can expel the contents of its cloaca, releasing a foul odor.

Reproduction is oviparous and seasonal, closely linked to river flood cycles. In the Amazon basin, breeding occurs from August to November, during the water receding period.

Females dig rudimentary nests in sandy banks or sometimes lay eggs directly on the ground. Clutch sizes range from 5 to 28 eggs depending on the regions. Incubation lasts several months, and hatching, which occurs between July and October, generally coincides with the rising waters.