Have you ever wondered why some animals live longer than others? It has been a mystery for centuries, but recent research has shed some light on this fascinating subject. By looking at the different life spans of various animals, we can understand why some species live much longer than others.
Factors such as diet, environment, and genetics all play a role in determining how long an animal will live. Discover six of the longest-living creatures on Earth and learn how they are adapted to a long life.
Immortal Jellyfish - Forever (maybe)
The immortal jellyfish, also known as Turritopsis dohrnii, is a species of jellyfish that has the remarkable ability to revert to its juvenile stage after reaching sexual maturity, which makes it capable of potentially living forever.
The life cycle of an immortal jellyfish begins with a planula larva which eventually becomes a polyp. Sexually immature polyps reproduce asexually through budding, while medusa releases gametes into the water and fertilizes them. From there, the fertilized eggs will develop into planula larvae and begin the cycle again.
In some cases, however, instead of developing into planulae, some medusae will revert to their polyp stage and start over again - thus achieving immortality!
While these jellyfish are technically immortal, many do not live forever. Transdifferentiation (the regeneration process) occurs when a medusa’s cells convert to the polyp stage. But if a polyp becomes sick in its immature state, it cannot regenerate and will die.
Additionally, many of these jellyfish die when predators eat them - they are immortal, not indestructible.
Sponges and Corals - 11,000 years
When you picture a sponge or a coral, you might think they are plants, not animals, but this is not the case. The main reason for this status is that they do not produce their food; instead, they use tentacle-like arms to capture passing prey and sweep it into their mouths.
Many sponges and corals can live for thousands of years. Still, one of the most impressive is the Antarctic sponge, which can live for 15,000 years or more. What’s its secret? Living in the frozen waters of the Antarctic. These large sponges can grow to 6.5 feet and live in depths between 49 and 472 feet. Still, these chilly depths make the sponges particularly difficult to study.
These sponges offer habitat to several smaller creatures, including isopods, amphipods, and polychaete worms. Plus, the extreme temperatures mean that all biological processes are slowed, thus expanding the lifespan of these extremely slow-maturing animals.
Ocean Quahog (Clam) - 400 years
The ocean quahog is a bivalve mollusk species in the North Atlantic Ocean. It is found in depths of up to 300 meters and can live for hundreds of years. It is an important food source for various marine organisms, including fish, whales, seals, and seabirds. And its long lifespan makes it an ideal subject for research into the effects of climate change on marine organisms because it can inform scientists how our oceans have changed over many years.
The oldest discovered Ocean Quahog was Ming, the 507-year-old clam captured off the coast of Iceland in 2006. The clam was named Ming, thanks to the dynasty that ruled China from 1368 to 1644. And this little mollusk was born in 1499, which scientists could calculate by counting the growth rings on its shell.
Greenland Shark 300-400 years
The Greenland shark is a shark found in the waters of the Arctic, Iceland, and Greenland. It is one of the longest-living invertebrates in the world and can live up to 400 years. It has a slow swimming speed, moving at an average of 0.76 mph, which is likely one of the reasons for its longevity.
Although they grow at a rate of only a centimeter per year, these sharks are some of the largest in the world, growing up to almost 16 feet.
Its skin contains a unique compound called trimethylamine oxide which makes its meat poisonous, but you can eat it once it is dried. These sharks may be enormous but are not considered a risk to people because humans do not tend to swim in the frozen waters that these fish inhabit.
Bowhead Whale - 200 years
The bowhead whale is a species of cetacean that belongs to the family Balaenidae. It is native to the Arctic and sub-arctic waters of the North Pacific and Atlantic oceans. The bowhead whale is one of the longest-living mammals on Earth, with some individuals estimated to be over 200 years old. It has a large, robust body that can reach lengths up to 60 feet and weigh up to 100 tons, making it one of the heaviest animals on Earth.
Its most distinctive feature is its large head with a distinctive white patch on its chin. Its diet consists mainly of zooplankton, small fish, and crustaceans.
It’s difficult to tell exactly how old these mammals are, but researchers use harpoon fragments and DNA to estimate their ages.
These scientists have come up with several reasons why these huge mammals live so long. Firstly, they discovered a gene mutation called ERCC1. This gene helps to repair damaged DNA and protects the whales from cancer. In addition, the gene PCNA involves slow cell growth, which leads to slow aging.
Galapagos Giant Tortoise - 150 years
With an average lifespan of 177 years, tortoises may well be the longest-living land animals. They are synonymous with longevity and are the first animal many would think of when picturing the longest-living creatures on Earth.
But how do they manage to live so long? The answer lies in their unique physiology and behavior. Tortoises have evolved to be incredibly resilient creatures, with slow metabolisms, low energy needs, and robust immune systems that help them fight off disease. They also practice hibernation and burrowing that help conserve energy and protect themselves from predators. All these factors combined give tortoises the longevity they are known for.
Also, tortoises possess gene variants linked to immune response, DNA repair, and cancer suppression. And these unique genes aren’t found in their shorter-living vertebrates relatives.