Friday, July 23, 2010

the olm lives over 100 years!!!

Video - the long-lived olm.

The Scientist | 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?