Galapagos Giant Tortoise
Galapagos Giant Tortoise
It’s not just the Galapagos Giant Tortoise size that’s worth noting; it’s also their age. They can live to be well over 100, with the oldest known to be 152! The oldest is not the most famous, though. Lonesome George was the last remaining Pinta Island Tortoise on the islands and, for a while, the world’s rarest creature. He died in 2012 at around 100 years of age. Like many of the animals on our list, giant tortoises have a slow pace of life, munching on grass and other vegetation, basking in the sun, and resting for up to 16 hours a day.
Red Sea Urchin
Red Sea Urchin
Red sea urchins are believed to be almost immortal and are known to live for over 200 years with no signs of ageing. They are far more likely to be eaten by a predator than die of an age-related condition, and a 100-year-old is just as healthy and able to reproduce as a young individual. Finding the age of these spiny echinoderms is possible by measuring the levels of carbon-14, a process known as radiocarbon dating.
Koi Fish
Koi Fish
The average lifespan for Japanese Koi is around 40 years though they can live a lot longer if living in the right conditions. One particular koi, named “Hanako”, was the remarkable age of 226 when she died in 1977. Scientists were able to estimate her age by counting growth rings in her scales.
Bowhead Whale
Bowhead Whale
Bowhead whales can live for over 200 years, which is longer than any other mammal. It’s not always easy to tell their age, though, as they spend their lives in the Arctic and sub-Arctic and can outlive the researchers that study them. One way to estimate age is to base it on fragments of harpoons left in the blubber of captured animals – one individual had harpoon fragments dating back to the 1800s! Another way is to use DNA to estimate lifespan, with scientists suggesting bowhead whales can live to the grand old age of 268!
Greenland Shark
Greenland Shark
Greenland sharks live for between 300 and 500 years and are the longest-living vertebrate. They take life very slowly, moving at an average of 0.76 mph. They grow about a cm every year, and females may not reach sexual maturity until they are 100 to 150 years old – that’s one long childhood! Despite their huge size and long lifespan though, these sharks have been a mystery to scientists for years. It was only recently that they discovered a new method of estimating age that involves radiocarbon dating the lens of the eye. New tissues are added to the lens every year and it is possible to tell the age by how much carbon isotope is present in the tissues.
Immortal Jellyfish
Immortal Jellyfish
Can you imagine being immortal? Reaching old age and then instead of dying, going back and starting again as a baby? To us, this is the stuff of dreams. For the immortal jellyfish, it is real life. These amazing animals start their life as larvae, known as planula, swirling around in the ocean. They then settle on the seafloor and become static polyps before transforming into swimming medusa. So far, so normal. But, if at any stage immortal jellyfish experience injury or stress from changes in their environment, they can go backwards to the polyp stage and start again. And they can do this over and over if they get the chance. Many won’t though as they become dinner for other animals.
Antarctic Sponge
Antarctic Sponge
Antarctic sponges can thank their environment for their long lifespans. These sponges, of which there are over 300, live approximately 325 to 6,500 feet underwater in extremely cold temperatures. This extreme environment slows down their growth rate and other biological processes, which results in remarkable longevity. A 2002 study calculated that one Antarctic sponge species, the Anoxycalyx joubini, could potentially live a phenomenal 15,000 years. The same study determined that the Cinachyra antarctica, which does not live as deep underwater as the Anoxycalyx joubini, can live up to 1,550 years.
Ocean Quahog
Ocean Quahog
The ocean quahog (Arctica islandica) is a bivalve mollusk that can live for 200 years. A lifespan of 100 years is common, with age measured by age marks formed in the quahog’s valves. With a habitat that stretches from the east coast of North America to Iceland, the Shetland Islands, and Cadiz, Spain, the ocean quahog has a broad range. Filter feeders, ocean quahogs bury themselves in the ocean floor to feed on microscopic algae.
