By Graham Duggan  

In The Nature of Things documentary, Aging in the Wild viewers meet species that exemplify all realms of age: longevity, reproductive health, social status and wisdom. From elephants to orcas, the animal kingdom has a good share of marathon agers.

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In the animal world, bigger animals often live longer. For small animals, life can move very quickly, and maintaining a high heart rate and metabolism wears out their bodies within a year or two (mice, shrews), but some of the bigger mammals can stick around a lot longer. With a slower metabolism and heart rate, larger animals have extended longevity. 

But there are some animals that live unexpectedly long lives, and they may surprise you.

Mole Rat: Ageless but ugly

Since they share a likeness to a sausage on legs with teeth — the naked mole rat can’t be considered one of nature’s ‘prettiest’ creatures, but they do have some very peculiar traits. They’re impervious to some types of pain, resistant to cancer and able to survive without oxygen for up to 18 minutes!

And when it comes to aging, the wrinkly pink rodents are one of a kind. These small social mammals live in large underground colonies and can live much longer than you would expect. Most similarly sized rodents live for about 6 years but naked mole rats can survive beyond 30 years, even remaining fertile in old age.

Naked mole rat

Photo: iStockPhoto/Getty Images

These mole rats also have another trick up their sleeve — they don’t age. As most mammals grow older, their risk of dying increases rapidly — but not mole rats. Their bodies avoid the cellular and physical degradation that normally comes with age and they remain youthful and healthy, even in their final years of life. This ability is special among mammals and could offer some hope for humans trying to avoid age-related diseases in the future.

Olm: Life in the dark

There are some reptiles that are well-known for their longevity — sea turtles can live to around 80 and there are records of some giant tortoises living to 250!

But we don’t usually give much thought to their slimy-skinned cousins, the amphibians. Many frog and salamander species can actually live to 10 or 20 years. The Maud Island frog from New Zealand is a real old-timer. Researchers have been running a long-term study on their population in the wild, monitoring some individuals that are over 40 years of age! Quite impressive for a 5 cm long amphibian!

But one of the longest-lived amphibians almost looks long in the tooth, even when young — blind, pale and slender, the ‘olm’ is a champion among aging amphibians. They are a strange species of salamander that evolved in the pitch-black caves of southern Europe, where the lack of light resulted in their reduced eyesight. In its dark, watery home, the olm takes nearly 16 years to reach maturity and even then, only reproduces every 12 years. But for a small animal, their maximum lifespan is incredible — roughly 102 years!

Olm

Photo: iStockPhoto/Getty Images

The olm doesn’t have a slow metabolism like other long-lived animals. One possible explanation? They’re lazy. These milky-white salamanders are extremely inactive, saving energy and only moving when it’s time to feed or breed. They also lead a stress-free life in their dark homes, without any predators to worry about.

Bowhead Whale and the Greenland Shark: Cold is key

When it comes to finding the oldest living animals, there’s really only one place to look — the ocean. Floating in water takes immense weight off limbs and joints, meaning bodies can grow massive. But surprisingly, the oldest in the sea isn’t the biggest of them all. Instead, the longest-lived mammal is a smaller, cold-loving one; the bowhead whale.

Living in the cold waters of the Arctic, the bowhead whale can grow to 20 metres long and weigh 100 tonnes — and live for more than 200 years! For this whale, cold is the key. Living in such a chilly environment, it has a lower body temperature and a slower metabolism, which means there’s less damage to its tissues over time. In fact, everything about them is slow. They only move 3-5km/h as they search for food.

Bowhead whale

Photo: Kate Stafford - Wikimedia Commons

In the Arctic, there is another animal that takes slow growth to its limit. The Greenland shark is a mysterious and seldom-seen shark that dwells in the deep, frigid waters of the Arctic. Growing only 1cm per year, it takes them a long time to reach maturity — 150 years before they can even reproduce.

Growing this slowly means that any large shark is very old, and researchers estimated one 5-metre shark to be as old as 390. Amazingly, that’s only middle age and it’s believed this species could potentially live up to 500 years old, making them the oldest-living vertebrate on Earth!

Greenland shark

Photo: NOAA Okeanos - Wikimedia Commons

Even though both the Greenland shark and bowhead whale could easily outlive all of us, their days on this Earth could be numbered. Because of their slow growth and reproduction, they are vulnerable to changes in their Arctic home, like climate change or deep sea fishing and oil exploration.

MORE:
Five aging tips from the wild
Meet some of the oldest living organisms on Earth

Clams: A ‘shell-tered’ life

There are however, other small creatures that have even outlasted the Greenland shark. Just like the olm, a sedentary lifestyle may just be the secret to a long life. In 2007, researchers were collecting specimens from the Icelandic shelf as part of a climate change study. One of those specimens, a clam, was nicknamed ‘Ming’ and ended up being the oldest recorded animal ever at 507 years old! To put that in perspective, when it was born, the Ming dynasty ruled China (hence the nickname) and Henry VIII was nine years away from becoming King of England.

By counting the number of bands in the mollusc’s shell, much like the rings of a tree, researchers were able to determine Ming’s exact age. Unfortunately, while the specimens were being collected for the study, they were frozen for preservation, ending Ming’s long life. However, it’s very possible that other clams, just as old as Ming or even older, are being enjoyed in steaming bowls of chowder every day.

Clams

Photo: iStockPhoto/Getty Images

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