Wednesday 9 February 2011


Image via Wikipedia
Aliens and myths. I look at the Olm and I think of aliens and myths. Some people in the 17th century thought they were baby dragons. They only reach 50 cm (19.7 inches), so the "baby" bit is quite important. It's actually an amphibian, but it doesn't make me think of salamanders or newts or things that definitely exist. No, instead I think of things that are likely (definitely, in my opinion, but I'm gonna be charitable) works of imagination and the unknown. The Olm just doesn't look like something that really exists. It's too pale. It's too long and thin. Its legs are too small. Worse of all, the head is too... plain, too... vacant. It has no face. I guess, when you get down to it, that's the real problem. And yet, it exists still. Does quite well for itself, too.

Image via Wikipedia
The Olm lives in underground cave waters of the Dinaric Alps, which is a mountain range in south-east Europe. It is exclusively cave-dwelling, the only such vertebrate in Europe, and is found nowhere else in the world. It's also completely aquatic, so it has absolutely no need for dry land or sunlight whatsoever. Which is strange, because I'm quite fond of both. Maybe I'd be different if I had gills but no eyes...

Actually, larval olms start life with both gills AND eyes. The gills remain for their entire life, which is obviously pretty good news. They also have simple lungs, they aren't so useful, but they're there. The eyes, on the other hand, they stop developing after a few months. Turns out that isn't enough for the olm, so they then start atrophying. Before you know it, they are completely useless and covered with skin such that the olm is totally blind. Well, not quite, they are still photoreceptive so they can at least sense a big ol' torch shining on them. Then again studies have shown that the olm's very skin is sensitive to light, so the eyes still aren't of any great use. No, the olm finds its way around via other means.

Olms have great taste. By which I mean they can taste and smell chemicals in the water and nearby food, such as crabs and snails. They also have great hearing so they can listen out for prey and use acoustics to work out exactly where the sound is coming from. They do this not only with their ears, but with the lateral line that runs down the sides of the body in fish and amphibians. They can also sense electric fields and, apparently, the magnetic field of dear old planet Earth. I'm sure this is great news for some reason. Once prey is found, olms swim over with eel-like undulations. They also have thin little legs with 3 toes on the forelimbs and 2 on the hind. They're more useful than the eyes, but probably not by much.

Image via Wikipedia
The food olms eat is tiny. Olms have tiny little mouths with tiny little teeth that are used to sieve out things that aren't tiny and little enough. They don't chew either, they swallow things whole, so... the food olms eat is really, really tiny. They can eat a lot of it though, and store the excess for when times get tough. This, along with reduced activity and a lowered metabolic rate means that the humble olm can survive up to 10 years without food. 10 years. Without food.

Time is often pretty weird for animals that live in perpetual darkness though. After mating, females lay about 70 eggs. It takes about 4 and a half months for the tadpoles to emerge and another 14 years before they reach sexual maturity. It's uncertain how long they can eventually live for. Some say it's about 60 years, others more like 100. Either way, that's a long time to be a baby dragon!


Zanck said...

great,, nice posting..

Joseph JG said...

Thanks, Zanck! Glad you think so.

Fuzzball Dave said...

AWESOME!!!!! wish i was an olm now D: except the no eyes part

Joseph JG said...

Hahahaha! I have no idea what to say to that, except good luck with your ambition.

Bill said...

A bit like mudpuppies in the US, but a little better looking!

Joseph JG said...

Yes! Olms and mudpuppies are actually closely related. Strange how walking into a dark cave and going blind made the olm all sleek and strangely attractive.