Animals that live underground are undoubtedly some of the strangest creatures on planet Earth. Having adapted over the years to living without light and little vegetation, underground animals are an evolutionary phenomenon. They are able to survive in the most extreme conditions, proving that life absolutely finds a way to adapt, even in the least likely of places.
As the only mammals in the entire world that can fly, bats are rather unique animals that live underground. However, most people are surprised to learn that they actually represent 20 percent of the entire mammal species. Thanks to their ability to fly, bats can be found in every corner of the world, except for Antarctica, the Arctic, and a handful of isolated islands.
Swiftlets are a type of bird that has adapted to living in underground cave environments. Similar to bats, they have adapted to their dark, underground environments by using echolocation. Unlike bats, however, their method of echolocation is audible to human ears.
Olms can be found in the waters of underground limestone environments in Italy, Croatia, Slovenia, and Herzegovina. These small amphibians survive on a diet primarily composed of insects, snails, and small crabs. Rather than chewing their food, they swallow it whole, and due to the fact that food is often scarce underground, olms can reabsorb their own body tissue and store nutrients in their livers for long periods of time. In fact, some olms can live for nearly ten years without eating. Not surprising, they have an exceptionally long average lifespan of seventy years.
Texas Blind Salamander
The Texas Blind Salamander is strikingly similar to the olm, and although they are not directly related, they do have many similarities. Instead of lungs, the Texas Blind Salamander has gills and feeds primarily on insects, snails, and shrimp. This unique species of salamander is native to Texas, especially in the areas surrounding the Edwards Aquifer in Hays County.
Second to bats, moles are probably the animals most associated with living underground. These small cylindrical mammals have become well-adapted to life underground. They have extremely tiny ears, velvety fur, small eyes, short hind limbs, and large paws that are well-suited for digging. They can be found throughout most parts of Europe, Asia, and North America.