How Long Do Olms Live? Possibly a Century in the Dark

How long do olms live?

The key figures come from a long-studied population of olms and from research on how they live in the wild. They are estimates, not ages read from individual animals, because there is no way to tell an olm’s age just by looking at it.

For comparison, most salamanders and frogs of a similar size live a few years to a couple of decades. The olm breaks that pattern by a wide margin.

How did scientists work out the olm’s lifespan?

The main evidence comes from an underground laboratory at Moulis in the French Pyrenees, run by the French national research organization CNRS. Olms have been kept there in cave pools since the 1950s, and researchers recorded births, deaths and breeding for more than half a century.

In 2011, a team led by Yann Voituron used these records to build a life table, which shows how likely an animal is to survive from one year to the next. Adult olms turned out to have very high yearly survival, with no clear rise in deaths among older animals. From this, the team calculated an average adult lifespan of 68.5 years and a predicted maximum lifespan of over 100 years. Some olms in the colony were followed for more than 48 years without showing signs of aging.

Why do olms live so long?

The cave environment plays a big part. Olms live in cold, dark water that stays at about 8–11 °C (46–52 °F) all year, with almost no predators and very little change from season to season. Biologists expect animals that face few outside dangers to evolve slower aging, because individuals have a good chance of surviving to breed again and again.

Everything about the olm’s life runs slowly. It is inactive for long periods, can go years without food, takes around 15 years to mature and breeds only about once a decade. Its eggs take about 140 days to hatch at 10 °C (50 °F).

Yet the full answer remains a mystery. The 2011 study found that the olm’s long life is not explained by its basic metabolic rate or by unusually strong antioxidant defenses, which protect cells from damage. Scientists see the olm as a promising model for learning how some animals slow down or escape the usual effects of aging.

A life in slow motion

Field studies show how unhurried olm life is. In an eight-year capture and recapture study in a cave system in eastern Herzegovina, published in 2020, researchers marked olms and found them again and again within a few square meters of the same spot. One individual was found in the same place over a period of about seven years, and how far olms had moved had little to do with how much time had passed.

This settled lifestyle saves energy in a habitat where food is scarce. Olms can store fat and sugar reserves in the liver, lower their activity when food runs short and, according to laboratory reports, survive up to about 10 years without eating.

How does the olm compare with other long-lived animals?

In most animal groups, bigger species tend to live longer. The olm is a striking exception. Among amphibians, the giant salamanders of China and Japan are well known for long lives in captivity, but they weigh hundreds of times more than an olm. You can read more in How long do giant salamanders live?.

Outside amphibians, the olm’s predicted maximum lifespan puts it in the same range as some tortoises and large parrots, although still far below record holders such as the Greenland shark and some clams. See the full list of the longest-living animals.

Why a long life matters for olm conservation

A long life comes with very slow breeding. A female olm may not lay her first eggs until she is about 15 years old and then breeds only about once every 12.5 years. Losses are replaced very slowly, so a population harmed by pollution can take decades to recover, if it recovers at all.

That is one reason the olm is listed as Vulnerable on the IUCN Red List. Its survival depends on keeping the groundwater of the Dinaric karst clean, because an olm that may live for a century will spend every one of those years in the same underground waters.