We humans may be living longer than ever, but our measly 71-year average lifespan pales in comparison to some of the creatures of the deep. Beneath the waves, animals can live for hundreds if not thousands of years – redefining the meaning of OAP.
From bowhead whales to sea urchins, koi fish to quahog clams, many sea creatures live to some truly incredible ages. But which ocean-dwellers live the longest? And what’s the secret to their astonishing longevity?
Here, we’re exploring the longest-living creatures in our seas, giving you the lowdown on why they live as long as they do.
Koi Fish
Koi fish may be one of the world’s best-loved pond and aquarium species, but they have a secret: they’re one of the longest-living carp species in the world. Usually, koi live from 25-30 years, but there have been several reports of fish living much longer – up to 200 years, in fact.
One such koi was the famous ‘Hanako’, a famed Japanese koi which is believed to have lived up to 226 years old. Following her death in 1977, researchers studied the growth rings on Hanako’s scales, revealing her true age. It’s not clear how Hanako lived so long, but she certainly survived through some incredible history – from the formation of the USA to the fallout of both World Wars.
Longfin Eel
Eels are surprisingly long in the tooth, with many species living 50+ years. This is primarily due to the slow rate at which they grow, so they don’t reach full maturity quickly unlike other marine creatures.
The longfin species is the perfect example of an eel’s longevity. These slow-growing ray-finned fish, native to Australia and New Zealand, have an average lifespan of 60 years, with the oldest-known longfin eel reaching 106 years old. It’s amazing to think that, despite their rudimentary design and anatomy, these primordial bottom-dwellers can sometimes outlive humans.
Bowhead Whale
While whales have a lot to contend with in the ocean, these grand mammals can really rack up the years. The bowhead whale, in particular, is a real stick-around, with scientists agreeing that many live upwards of 200 years – making them one of the longest-living mammals on Earth.
According to recent studies into the longevity of bowhead whales, scientists think they may have discovered the secret behind the species’ long life. Studies into the bowhead’s genome reveal that they remain disease-free considerably longer than other whale species, and that they may have developed a unique way to fend off ageing and promote cell repair. Clever stuff.
Red Sea Urchin
Although they may not look it, sea urchins are very much alive. Characterised by their imposing spiny shells, these weird creatures can live phenomenally long lives at staggering depths – with the red sea urchin being among the longest-living urchin species.
Native to the Pacific Ocean, particularly North America, red sea urchins have an average lifespan of 200 years – meaning they’re almost as old as the country they inhabit. The secret to their long life comes down to the minimal energy they consume, as well as the slow rate at which they grow and develop.
Greenland Shark
Often described as dinosaurs on Earth, Greenland sharks are an ancient shark species native to the cold Atlantic waters of Greenland, Iceland and the Arctic. These primaeval-looking animals regularly live 200+ years, with some of the oldest known examples living 400 years – placing them among the longest-living vertebrates in the world.
What’s the secret to Greenland sharks’ long lifespan? Researchers agree it’s all down to the rate at which they grow, with the average shark not reaching full maturity until they’re a century old! That’s like being born in 1920, and not being allowed to vote until this year! It also has a lot to do with the cold waters they’re native to, which slows metabolism and cell degeneration.
Quahog Clam
If you thought Greenland sharks were old, wait until you hear about quahog clams, one of the ocean’s oldest crustaceans. Many collected examples of this hard clam species, which is native to North and Central America, have been calculated to be more than 400 years old – meaning that they were around since before the start of the English Civil War!
Indeed, the historical significance of quahog clams wasn’t lost on researchers, who named one of the oldest examples as ‘Ming’, in reference to the Ming Dynasty which ruled China from 1368 to 1644. It’s certainly impressive to think of all the historic moments these simple sea creatures have been alive for.
Orca
Everyone knows that orcas are among the smartest marine mammals in the ocean, but did you know that they’re also some of the longest-living? Some orcas alive today are thought to be over 100 years old, and it’s believed the secret to their longevity rests on their family ‘pod’ mentality.
Orca live in extended families called pods which are overseen by a matriarch. This dominant female animal is protected throughout her life by her offspring, meaning that she tends to live the longest. For the past decade, researchers in the US have been tracking a pod led by ‘Granny’, an old, healthy matriarch who is estimated to be 104 – and counting.
Deep-Sea Sponge
You may think we’re bending the definition of ‘creature’ a little with this entry, but deep-sea sponges are very much alive – and boy do they grow to be old. According to some studies, deep-sea sponges can reach thousands of years old – with the oldest known example estimated to have reached the grand age of 11,000!
Deep-sea sponges grow at tremendous depths, forming sprawling and often complex structures which, in turn, attract the attention of the creatures’ preferred prey, plankton. Some of the largest known deep-sea sponges, which are about the size of a car, are thought to be the oldest examples, with an average lifespan of over 2,000 years – meaning they’ve been around since the time of the Romans.
Immortal Jellyfish
The term ‘immortal’ may get bandied around a lot in superhero movies, but until recently, the notion of eternal life was nothing more than fiction. However, back in the 1980s, scientists made a startling discovery which defied what we thought we knew about everlasting life: the immortal jellyfish.
The immortal jellyfish, or turritopsis dohrnii, is a small species of jellyfish which is classed a biologically immortal. Found in tropical waters, the secret to this creature’s eternal life lies in its ability to revert to sexual immaturity, whereby it effectively clones itself. Given its amazing and seemingly endless lifespan, the immortal jellyfish is considered one of the world’s most important marine species for biological and pharmaceutical research.
So, there you have it, a look at some of the longest-living marine creatures in our oceans. Looking for more from Blue Planet Aquarium? Head to the blog for more fun features and guides, or to plan your visit to our aquarium, visit the homepage.