How Slovenia is helping its ‘baby dragons’

The eyeless subterranean salamanders that live in the watery depths of Postojna Cave are under threat – but there’s hope in sight

Robin McKie

Sunday 27 August 2017 10.30 BST

Postojna Cave in Slovenia is one of Europe’s longest cave networks and one of the world’s most spectacular subterranean tourist sites. Hundreds of thousands of visitors come here every year to gaze at its wonders: its huge stalactites and stalagmites, its curtains of coloured rock and bridges that have been carved out of the local limestone by the river Pivka over millions of years.

Given such glories, it is not surprising that few tourists take note of the two concrete huts draped with black polythene that have been erected in a shadowy alcove in one obscure part of the 24km-long labyrinth. But the huts contain wonders of their own. In racks of trays of water, scientists have placed specimens of one of the world’s strangest creatures: the blind aquatic salamander Proteus anguinus – or olm, as it is known locally. It constitutes a project that could have profound implications for the future of these remarkable creatures.

Slovenia is extremely proud of its remarkable little blind salamander which featured on the country’s pre-Euro coins

“We now have 21 baby olms flourishing in our trays,” said Primoz Gnezda, a biologist working in Postojna Cave. “For the first time we have witnessed the hatching of proteus larvae – and, after one year, they are all healthy. And that gives us hope we can save our olms for the future.”

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Weird amphibians found at record depth in dark underground lake (Olms in Croatia) - via Herp Digest

By Vedrana Simičević, New Scientsts, 6/22/17—Olms, amphibious salamanders that live in the western Balkans and Italy – are extreme divers, reaching depths in excess of 100 metres in dark lakes inside limestone caves.

A team of divers and biologists has now found the curious creature 113 metres below the surface of such a lake in Croatia.

“This was the deepest finding of the olm ever recorded,” says team leader Petra Kovač-Konrad.

Proteus anguinus is commonly dubbed the “human fish” because of its pinkish pale skin, and the creatures were once believed to be baby dragons. They are noted for their slow lifestyle and long lifespan: these blind animals can live up to a century.

Little is known about olms, and it is a race against time to find out more as the salamanders’ underground habitat is being contaminated by pollution from human activities on the surface. The animals are notoriously difficult to observe in their natural habitat, except through the complex and dangerous skill of cave diving – although technology may be about to change that.

Croatian and international cave divers have found five new olm habitats in the past six years as part of the project run by Croatian association Hyla. The lake where the creature was seen at record depth, Zagorska pec, is of particular interest as, unusually, several specimens have turned up there.

“We spotted specimens at many different depths in the lake, which confirms the assumption that depth of the water isn’t the stress factor for the olms,” Kovač-Konrad says. “We also noticed that olms prefer specific parts of the cave system with less stressful conditions, such as slower water flow or bigger amount of sediment.”

Recent discoveries of potential new habitats have been made using environmental DNA from cave water once it surfaces, and there are efforts to breed olms in captivity. Most observations of their behaviour involve captive animals, mainly in underground laboratories such as the ones in Postojna or Tular caves in Slovenia.

“Study of the olms in greater depths is extremely important, especially when done by divers focused on conservation,” says biologist Gregor Aljančič, head of the Tular cave laboratory. He suspects the olm will be found even deeper than the current record. “Our previous findings indicate that Proteus can withstand significant pressure.”

But it could be that the depths cave divers can reach will be the main determiner of how far down we find olms, says speleologist and biologist Gergely Balázs, of the international Proteus Project based in Bosnia and Herzegovina.

As for conserving the animals, information about their geographical spread will be more important than knowledge of the depths they can live at, he says.

“In some caves all across the olm’s distribution range you would see only one, and in other places you would see 200 of them during a dive,” says Balázs. “And there are some places where you can’t find any, but we still don’t know why.”

Balázs’s team is now trying to install infrared cameras in the caves to film the olms going about their business.

 

Olm eggs: First two Slovenian 'dragons' emerge

By Jonathan Webb Science reporter, BBC News

4 hours ago

After a four-month wait, the eggs laid by a peculiar salamander in a Slovenian cave have started to hatch.

Ghostly pale and totally blind, olms - fondly known by locals as "baby dragons" - only reproduce every 5-10 years and are thought to live to 100.

This clutch of eggs started to appear in January in an aquarium in Postojna Cave, a tourist destination where the creatures have lived for millennia.

Observing baby olms develop and hatch is a rare opportunity for science.

The first of 23 developed eggs hatched on 30 May; a second baby olm (pictured below) was slowly wriggling out of its egg on Wednesday night.

"It is the end of one part of the story and the beginning of a whole new chapter: feeding and living without the egg," said Saso Weldt, who looks after and studies the olms at Postojna Cave.

He told BBC News nobody witnessed the first egg hatching, but the moment was captured thanks to an infrared camera.

"I was in the cave doing some other biological work. Since we have all the eggs on an IR camera, we saw that one was missing. Then you rewind and suddenly you realise, something has happened."

Mr Weldt and his colleagues hope to see a full count of 23 healthy hatchlings within a few weeks.

The staff at Postojna have been consulting amphibian experts to help them care for the fragile eggs, including a French team that has studied the olms in an underground mountain lab since the 1950s.

That laboratory is the only other place where these animals have ever been observed emerging from their eggs.

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