Tailless Caecilians: Caeciliidae

Physical characteristics: Cayenne (kye-EHN) caecilians are water dwellers. They have a fin on the back that runs the length of the body. The body is flat from side to side, making the caecilians look more like eels than earthworms. These caecilians have large passages inside the head between the nose and the roof of the mouth, and they have well-developed lungs. Cayenne caecilians have one ring per vertebra, and the grooves between the rings are deep. These caecilians are gray to dark blue or black. Adults are 12 to 22 inches (30 to 55 centimeters) long. The cloaca region is flat, forming a disk that is paler in color than the rest of the body.

Cayenne caecilians live in slow-moving, warm tropical rivers and streams. (Illustration by Brian Cressman. Reproduced by permission.)

Geographic range: Cayenne caecilians live throughout the Guianas and the Amazon region of South America.

Habitat: Cayenne caecilians live in slow-moving, warm tropical rivers and streams.

Diet: Cayenne caecilians root around in the mud of the sides and bottoms of the waterways in which they live. They eat shrimp, insect larvae, and small fish. These caecilians have a strong bite mechanism. In captivity cayenne caecilians feed on pieces of earthworms and liver. Cayenne caecilians seem to sense the presence of prey by touch or motion.

Behavior and reproduction: Cayenne caecilians share burrows with one another and leave the burrows at sunset to look for food. These animals have mucus glands all over their bodies. The mucus is poisonous and tastes bad to fish. Predators of cayenne caecilians include large fish, snakes, and birds.

Cayenne caecilians mate by nudging and coiling around each other. The male places sperm in the female, and fertilization takes place inside her body. Cayenne caecilians give birth to fully developed young, which are born seven to nine months after fertilization. A female can give birth to six to fourteen young at a time. The developing young have gills that are shed soon after birth. The developing young have teeth they use to eat a nutrient liquid made by the female's egg ducts. These teeth also are shed soon after birth, and then the adult teeth grow in.

Cayenne caecilians and people: Cayenne caecilians are sold in aquarium stores as rubber eels or black eels. Only rarely do store owners identify them as amphibians (am-FIB-ee-uhns), which are vertebrates (VER-teh-brehts), or animals with a backbone, that have moist, smooth skin; are cold-blooded, meaning their body temperature is the same as the temperature of their surroundings; and, in many instances, but not in the case of cayenne caecilians, have a two-stage life cycle.

Conservation status: Cayenne caecilians are not considered threatened or endangered. They have been collected extensively by fishermen, scientists, and pet dealers. ∎