Blind salamander with translucent skin that can live in total darkness for up to a century stayed in the same spot for more than Seven Years, study claims - via Herp Digest

Olms live in deep underwater caves and can go years without food 

The amphibians conserve energy by not moving and can be stationary for years 

One animal was found in the exact same place after a total of 2,569 days 

By Joe Pinkstone for Mailonline, 2/4/20

A rare cave-dwelling salamander has been found in the exact same spot after more than seven years, and scientists think it has not moved at all in that time. 

Scientists swam to the underwater cave where 19 of the salamanders, known as olms, live in Bosnia and Herzegovina.

Several dives over eight years tracked their movement and found most moved less than 33 ft (10m) between 2010 and 2018, and around 16ft (5m) was the norm. 

The most active olm moved 38 metres in just 230 days while one was found at the exact same spot after 2,569 days.

Little is known about the creatures as most of the previous studies on them have been done in laboratories but researchers believe one animal in an underwater cave in Bosnia and Herzegovina didn't move for 2,569 days”

Little is known about the creatures as most of the previous studies on them have been done in laboratories but researchers believe one animal in an underwater cave in Bosnia and Herzegovina didn't move for 2,569 days 

WHAT ARE OLMS? 

The olm is a blind, cave-dwelling salamander, also called the proteus and the 'human fish’.

The olm was once described as a baby dragon on account of its small, snake-like body

It is thought they conserve energy to a maximum and only move to mate, which happens once every 12.5 years. 

They have evolved a translucent skin and no longer develop working eyes as they live in the pitch black world of underwater caves. 

They can live for several decades, with the average life expectancy of 70 and a maximum lifespan of more than 100 years.

Researchers tagged 19 olms in the cave system with a harmless ink that made them identifiable. 

They then returned eight years later and assessed how far they had moved. 

The researchers do state it is possible the animals moved between assessments and returned to the same spot, but don't know enough about their daily routines in the wild.

The amphibians are well-adapted to a stationary lifestyle. 

It is thought they conserve energy to a maximum and only move to mate, which happens once every 12.5 years. 

They can live for several decades, and some believe up to a century. 

They have evolved a translucent skin and no longer develop working eyes as they live in the pitch black world of underwater caves. 

Olms have evolved a translucent skin and no longer develop working eyes as they live in the pitch black world of underwater caves

"Olms retain the red, feathery gills of its larval form even when it becomes sexually mature at adolescence pictured). It stays this way for the rest of its remarkably long life.”

Olms retain the red, feathery gills of its larval form even when it becomes sexually mature at adolescence pictured). It stays this way for the rest of its remarkably long life.

'They are hanging around, doing almost nothing,' Dr Balázs told 

Olms can survive years without food and feed on small crustaceans which are uncommon.

Little is known about the creatures as most of the previous studies on them have been done in laboratories.

Therefore, researchers have sparse data to tell them how the creature live in the natural habitat. 

Gábor Herczeg from Eötvös Loránd University in Budapest, Hungary, who co-authored the study in the Journal of Zoology, said: 'We do not know the daily activity.'

Meet 100-year old Salamander (Via HerpDigest)

Meet 100-year old Salamander
The Scientist, by Jennifer Welsh 7/21/07

A blind, cave-dwelling amphibian appears to live for more than 100 years, an inexplicable feat that may eventually (when explained) provide insights into aging in other species.

But first, scientists have to unravel the mystery of how the species -- known as "human fish" -- achieves such longevity. "We cannot, at this time, say how this animal manages to survive such a long time," said eco-physiologist Yann Voituron, from the Université Claude Bernard - Lyon, first author of the study published online today (July 21) in Biology Letters. He was able to calculate the animal's extreme longevity by studying over 50 years of birth and death records of a 400-animal captive breeding colony at the Station D'Ecologie Expérimental du CNRS in Moulis, France.

The human fish, also called an olm, is a small, pale salamander, weighing between 15 and 20 grams, that has evolved extreme longevity living blindly in the caves of Europe. It can also live for a year without eating and can survive in hypoxic conditions for years.

Voituron's calculations from the weekly records of the colony predicted the olm's maximum lifespan to be over 100 years, with an average lifespan of 68.5 years. The olm's longevity exceeds that of other amphibians of its size by several times, much the way humans live about four times longer than other animals their size.

Indeed, the runner-up for longest living amphibian, the giant Japanese salamander, weighs in around 25kg, 1000 times more massive than the olm. "It is rather strange to discover that [so small an] animal, weighing about 15-20 grams, is able to survive more than a century," said Voituron. "It's the first time we found this kind of profile for a vertebrate [other than humans]."

In one respect, the amphibian's longevity is not surprising, since it has a natural lack of predators, enabling it to evolve to favor long-term survival and less frequent reproduction.

In other respects, however, the human fish's ability to live 100 years makes no sense, biologically.

Several physiological traits are normally associated with long-lived animals: larger size, low metabolic rates, and high protection against oxidative stress. Examples include giant tortoises and elephants - animals that have large body masses and low basal metabolic rates.

The olm, however, doesn't show any of these traits. So why does it live so long?

John Speakman, an energetics researcher at The University of Aberdeen said in an email that the olm is "a fascinating animal." And in consideration of recent findings that the naked mole-rat, the longest-lived rodent at 28 years, is immune to elevated levels of oxidative stress, the olm "cast[s] further doubt on the oxidative stress theory of ageing."

The authors have suggested two possible explanations. The first is the animal's exceptional laziness -- it only eats about once a month, and doesn't have to run away from predators, because it has none in its natural environment. Because it doesn't extend much energy, its metabolic rate mostly stays at its baseline rates, while most animals' metabolisms are often running much above their basal rate. "This could be a way to avoid free radical production, and thus aging," said Voituron.

Their second theory, supported by data they've collected since publishing the paper, is that the olm's mitochondria function differently from normal mitochondria -- they are able to process more ATP with less oxygen, thereby reducing their free radical output. Voituron is currently learning more about the olm's mitochondrial functioning, and comparing it to other species.

Caleb Finch, an aging researcher at the University of Southern California, said he believes the human fish could be an example of "negligible senescence" -- extremely slow aging without an increase in disease or loss of reproduction.

"This is a new [longevity] example that is very valuable," said Finch. "It documents another group of vertebrates, with actual lifespan data, that show extremely slow aging."

Y. Voituron et al., "Extreme lifespan of the human fish (Proteus Anguinus): a challenge for ageing mechanisms," Biology Letters AOP July 20, 2010 DOI: 10.1098/rsbl.2010.0539