Caecilians are a group of limbless amphibians often mistaken for earthworms or snakes due to their appearance. These animals are one of the three main orders of amphibians, alongside frogs and salamanders. Their name originates from the Latin word for “blind,” which alludes to their typically small or absent eyes. Despite their hidden, burrowing lifestyle, they represent a diverse lineage of amphibians with unique adaptations.
Physical Characteristics
The bodies of caecilians are elongated and cylindrical, marked by ring-like folds in the skin known as annuli, which give them a segmented look. Their skulls are robust and bullet-shaped, an adaptation for a life spent burrowing through soil. Skin is generally smooth and may contain small, embedded calcite scales. Colors can range from dark gray and purple to more striking shades of blue or yellow.
A distinct feature of all caecilians is a pair of short, sensory tentacles located between their eyes and nostrils. These retractable structures are chemosensory, meaning they help the animal detect chemical cues in its environment, which is useful for locating prey underground. Their eyes are often very small and can be covered by skin or even bone, resulting in limited vision that likely only distinguishes between light and dark.
Habitat and Distribution
Caecilians are primarily found in the humid, tropical regions of the world. Their geographic range includes South and Central America, parts of East and West Africa, and Southeast Asia, including India and Sri Lanka. They have not been found in Madagascar or Australia. This distribution suggests they have ancient origins, possibly dating back to before the continents separated.
Most species have a fossorial (burrowing) lifestyle, creating tunnels in damp soil, mud, and leaf litter in forests, savannas, and wetlands. While the majority are terrestrial, some species are partially or fully aquatic, inhabiting streams and ponds within their tropical ranges.
Diet and Unique Reproduction
As carnivores, their diet consists of earthworms, termites, insects, and other small invertebrates found in their habitats. They use dozens of sharp, needle-like teeth, sometimes in two rows, to grip their prey, which is then swallowed whole.
While some species lay eggs that are guarded by the female, others give birth to live young. A form of parental care known as maternal dermatophagy has been observed in some species. The young possess specialized teeth that allow them to peel off and consume a specially grown outer layer of their mother’s skin. This skin is rich in fat and nutrients, providing the offspring with the nourishment they need to grow rapidly.