Olm

Names & Nicknames: Olm, Proteus, blind cave salamander, cave salamander, white salamander, and the human fish

Size: These slender noodles are usually around 20-30cm and weigh as much as a kiwi fruit or even less. However, some ladies (the females tend to be bigger) can reach 40cm!

Smell: When you are as blind as an olm (there is no need to see when you live in constant darkness), you may turn to other organs and senses, like their sensitive schnozes. Olms can sense tiny traces of organic compounds in water to help sniff out their prey.

Communication: Why chat when you spend most of your time alone, motionless in the darkness? When they get in touch with their fellow olms, they do this mainly by releasing pheromones that others can sniff out.

Favourite Hangout: Olms love the crisp, clear water of a nice underground cave system. They're found across the Dinaric Alps which stretch from Northeast Italy to Bosnia and Herzegovina – Europe's only cave-adapted vertebrates!

Favourite Snack: Crustaceans, snails, worms and insect larvae. In captivity, they even snack on the eggs of other olms! However, we don't know if this gruesome behaviour happens in the wild of their crisp cave ponds.

Eating Habits: Masters of the sit-and-wait strategy – lying in the water and waiting for their prey to come to them. They have electroreceptors, a bit like an angelshark, that sense weak electric fields of nearby prey. Once caught, olms don't waste their time chewing, preferring to swallow their food whole. But can you blame them when they sometimes go years without a meal?

Love Language: Olms are thought to mate during the late winter or early spring, when a male releases sperm capsules into the water that the female picks up for internal fertilisation. The female will then go and lay 10-70 eggs in a safe spot where they can stay developing for over 4 months!

If you see them: We hope you wrapped up warm and brought a head torch! So little is known about these creatures since olms live in such a hard-to-reach and inhospitable (for humans at least) habitat, so we hope you remember your way out of the cave!

Red Flags: Olms are VERY fussy when it comes to their cave water. It needs to be cold, clear and clean, which, luckily, is usually the case in their Balkan cave homes. However, this is changing, as activities like land development, agriculture, and waste disposal increase in the area, generating pollutants that can creep into the olm's watery habits, spelling disaster for the sensitive souls.

Epic Journeys: Olms do literally the opposite of epic journeys, they do epic staycations. An average journey length for an olm is 5 metres… per YEAR. Some olms do even less than that, with one olm having not moved for 7 whole years.

Glow-up: Olms have really embraced their childhood nostalgia and just refuse to grow up – quite literally. As olms develop, unlike most other amphibians (like the goliath frog) they keep many of their larval characteristics such as gills and tails. This phenomenon is called neoteny and is also seen in amphibians such as axolotls.

Facts: Olms can be ancient. These mini-dragons aren't sexually mature until around the age of 12 and they may live for up to 100 years, so there could be olms out there that were around during the roaring 20s!

Who are they in the friendship group: They really don't get out much and they just won’t grow up.