The mysterious olm has no eyes and colourless skin as it lives in total darkness in deep, watery caves.
The olm is a type of salamander that lives in deep caves where it's dark all the time. Because it spends all its time underground, this creature has no eyes and no colour in its skin. Bizarrely, if you raise an olm outside its natural cave habitat, it can develop very basic eyes.
Olms live in caves in parts of Slovenia, Italy and Croatia. This unearthly-looking creature can live for more than 50 years but it cannot breed until it is a teenager, rather like a human in fact. The olm is also known as the humanfish, the cave salamander or the white salamander.
Most amphibians leave the water to breed, but the olm lives its entire life underwater. They have fewer digits than other amphibians, with three digits on its front legs instead of the usual four, and only two digits on the back legs, even though most amphibians have five.
All in all, it's a strange, sad looking creature, with small skinny limbs and no manners - it does not chew its food, it swallows it whole!