All About Caecilians, The Creepy Underground Snakes Of The Amphibian World

If you think snakes are creepy, then you might not want to know about caecilians, a group of animals that are somehow even more upsetting to look at. They are long, limbless animals that look like they haven't evolved in billions of years. These snake-like amphibians are not exactly rare, but their subterranean lifestyle means that most people can go their whole lives without seeing one, even if they are living just a few feet below us. 

There are all sorts of freaky facts about caecilians that are just as intriguing as their unusual appearance. They have specialized sense organs that allow them to hunt underground and make some pretty unusual sacrifices when it comes to raising their offspring. If you're curious to know more about what these bizarre creatures are like, this will be a perfect introduction to one of the most interesting animals on Earth.

  • Babies Feed On The Flesh Of Their Own Mothers

    Babies Feed On The Flesh Of Their Own Mothers
    Video: YouTube

    If you thought the most disturbing thing about caecilians was their appearance, think again. Caecilian motherhood is as terrifying and brutal as an Eli Roth film, and that's saying something. At least one species of caecilian nourishes their offspring with their very own skin.

    A caecilian mother can lose up to 14% of her body weight while raising her young, all of it being literally torn off of her body. The moms don't seem to mind that much, as they are relatively calm during feedings. Caecilians take excellent care of their young, rivaling mammals when it comes to paternity skill. They are certainly some of the most devoted mothers in the animal kingdom.

  • Most Caecilians Live Underground

    Most Caecilians Live Underground
    Photo: Ariovaldo Giaretta / Wikimedia Commons / CC BY-SA 2.5

    The vast majority of the over 100 species of caecilians spend the majority of their time underground. A few South American species, like the rubber eel, are known to be aquatic and have evolved to spend their lives swimming rather than digging. Because of their mostly subterranean lifestyle, caecilians have little need for their senses of sight and hearing.

    In most species, the eyes are recessed under the skin and can do little more than detect light and dark. Caecilians don't even bother with ear holes, so they likely don't hear in the traditional sense of the word. Researchers have discovered a specialized organ in their skulls that is able to detect vibrations, which is the closest thing to a sense of hearing that they have.

  • They Are The Only Amphibians With Tentacles

    They Are The Only Amphibians With Tentacles
    Photo: Wilkinson M, Sherratt E, Starace F, Gower DJ (2013) / Wikimedia Commons / CC BY 2.5

    Because of their subterranean habits, caecilians have had to adapt specialized organs to guide them through the darkness. Between their eyes and nostrils is a hidden, retractable tentacle that can be used to sense their environments. The tentacles pick up chemical signals that help inform the caecilian about their environment and any potential prey in the vicinity. 

  • When Threatened, Their Skin Oozes A Toxic Enzyme

    Caecilians have a moist skin which hides a bit of a secret. They have a series of toxic glands below the skin that are able to secrete a potent poison when they are being threatened by a potential predator. Caecilians are not the only amphibians who use toxic skin excretions as a defense. Poison dart frogs are infamous for their ability to produce powerful toxins. Like poison dart frogs, many species of caecilian are aposematic, meaning that they sport bright colors to warn potential predators that they are dangerous and should not be eaten.

  • Their Mouths Are Filled With Sharp Teeth

    Their Mouths Are Filled With Sharp Teeth
    Video: YouTube

    While caecilians may look like snakes, there is something about them that gives off the impression that they are softer and more harmless than their reptile doppelgangers. While they aren't dangerous to humans, caecilians are predators who tear up their prey with their dozens of tiny teeth. They use their teeth tear off chunks of their prey, much like the babies do with the mothers. These carnivorous amphibians subsist on a diet of worms, insect larvae, and aquatic species will occasionally eat small fish.

  • The Largest Ones Can Be Five Feet Long

    There are quite a few different species of caecilian, and most of them aren't very large. The smallest ones are about three inches in length, but there is a species that can grow to a monstrous five feet. Caecilia thompsoni, a species indigenous to South America, is the longest species of caecilian and one of the largest amphibians in the world. They only weigh about two pounds, but that's not very comforting when you run into a five-foot, blind worm-snake in the middle of the jungle.