The olm and the secret of long life

A blind, cave-dwelling amphibian could hold the secret to ageing, according to research published in the Royal Society’s journal, Biology Letters. The olm, Proteus anguinus, can live for up to 100 years, despite defying most existing explanations of the physiology of ageing.

Longevity has previously been associated with large body size and slow metabolic rate or high protection against oxidative damage, but the “human fish” displays none of these characteristics. An average sized olm is around 20–30cm long, has a metabolic rate similar to that of other amphibians and no mechanism to repair oxidative damage.

In contrast, the second longest living amphibian, the giant Japanese salamander, can grow to 2m.

The oxidative damage theory had been supported by the physiology of the naked mole rat, the longest-living rodent, which can live for up to 28 years. This underground dwelling creature can substantially reduce its metabolic rate during times of hardship, thereby reducing oxidative damage.

And at 20m long and thought to live for up to 200 years, the world’s longest living mammal, the bowhead whale, supports the theory that size matters in relation to longevity.

The olm does, however, inhabit a predator-free environment, a significant contributor to a long and peaceful life. It is the only cave-adapted vertebrate in Europe and inhabits caves mainly in Slovenia and Croatia.

The researchers conclude: “This species raises questions regarding ageing processes and constitutes a promising model for discovering mechanisms preventing senescence in vertebrates.”

The peculiar nature of the olm has been recognised for hundreds of years. Charles Darwin described the amphibian in his ‘Origin of Species’ as an example of the reduction of structures through disuse.