Blind and ghostly pale or disturbingly fleshy, these exceptionally creepy creatures wriggle through the dirt under the surface of the earth or along slick rock surfaces in subterranean caves. They’re not cute – in fact, some of them are really amazingly ugly – but these 7 wonders of the underground animal kingdom are certainly fascinating.
Fairy Armadillo
From its name, you might expect the pink fairy armadillo to be cute – maybe even beautiful in an otherworldly way. You’d be wrong. It’s hard to find an armored creature with pink scales and massive claws cute, despite its cuddly, furry underbody. The smallest species of armadillo, this nocturnal subterranean animal is found in the dry grassland and sandy plains of central Argentina. It’s a ‘sand swimmer’, using its front claws to move through underground spaces in a manner similar to swimming through water.
Star-Nosed Mole
This might just be the weirdest mammal on earth, shy of the platypus. The star-nosed mole has an entirely unexpected face that would seem more at home under the sea than under the ground – not to mention those terrifying claws. These rodents have snouts with a ring of 22 octopus-like tentacles that help them find and capture worms and other small prey within seconds. Using high-speed video cameras, researchers have discovered that not only are these moles the fastest mammalian foragers on earth, they can also sniff underwater using air bubbles.
Ajolote Mexican Mole Lizard
You might think this strange little creature was a particularly large earthworm if you just saw part of its body while digging. But check out those front legs – and its face. The ajolote, also known as the mexican mole lizard, is an elongated burrowing reptile with tender-looking pink skin and small but developed forelimbs that help it claw its way through the earth. It spends nearly its entire life underground, emerging only when its subterranean homes are flooded.
Naked Mole Rat
Is this the world’s ugliest animal? The naked mole rat definitely has a face only a mother could love. This burrowing rodent has almost no hair and wrinkled pink or yellowish skin. It has tiny eyes, and can barely see at all. Those massive teeth are used to help it dig, and just beyond them is a seal of skin that helps prevent soil from filling its mouth. It’s the only known mammal thermoconformer, meaning it doesn’t regulate its body temperature like other mammals – its body temperature tracks ambient temperatures. Its metabolic rate is very slow, so it can go long periods without oxygen or food. Interestingly, the naked mole rat has a lack of pain sensation in its skin.
New Zealand Glow Worms: Arachnocampa
Enter certain caves in New Zealand and you might feel as if you’ve stepped into another galaxy. Against the black and umber tones of the cave walls are glowing splatters and threads in white, blue and green. These threads, made of silk dotted with mucus, are the traps of the larvae of a fungus gnat species. Arachnocampa larvae spin their nests out of silk on the cave ceilings and drop up to 70 of these threads, which can measure up to 16 inches long. The bioluminescent glow of the mucus attracts prey to the threads; in some species, that mucus is poisonous.
Ghost Slug
As if leeches weren’t creepy enough, there’s the appropriately named Ghost Slug, which is not only blind and pale, but bloodthirsty, and armed with razor-sharp teeth. It’s been spotted all over Wales, lurking in the soil of gardens where they slurp up worms ‘like spaghetti.’ The lack of eyes and body color could indicate that it evolved in caves. Scary as they sound – and as much damage as they can do to gardens – they’re not a threat to humans.
Blind Cave Eel
This blind cave eel is known as the olm, or proteus, and eats, sleeps and breeds underwater in caves found within the Dinaric Alps. It’s occasionally called ‘the human fish’ by locals because of its pale pinkish flesh. While it can’t see, its other senses are very well developed, and though it has external gills into adulthood, it’s not an amphibian – it’s entirely aquatic, the only species in the proteus genus. Its skin itself is sensitive to light, and it can sense low concentrations of organic compounds in the water, helping them sense both the quantity and quality of prey.

