There are millions of living creatures on Earth, and we humans are just one of them. Some of these creatures have gone extinct; some have existed for hundreds of years, while others recently evolved from older creatures. This makes us wonder what the oldest animals on earth are. So, in this post, we’ll discuss five of the oldest known animals on earth.
Greenland Shark
The Greenland shark is found in the North Atlantic and Arctic waters. It belongs to the family of sleeper sharks (Somniosidae). Its species name is Somniosus microcephalus. Scientists can detect their age by radiocarbon dating a particular protein formed in their eyes before birth and remains throughout their lives.
Courtesy: National Geographic
Through this process, we now have an idea of the average age of a Greenland shark. A particular Greenland shark was examined and was discovered to be about 392 years old. They are now known to have a lifespan between 250-500 years. Greenland sharks attain a stage of sexual maturity at about 150 years.
Jellyfish
Jellyfish are known to have existed long before land-living animals came into existence. Scientists have detected the age of the jellyfish by examining soft fossils found in rocks. The results of these tests are astonishing!
Courtesy: Wikipedia
Jellyfish were thought to be about 300 million years old before. However, recent findings have revealed that these organisms have existed for about 500 million years. The jellyfish has a short lifespan, but under adverse conditions, some species can turn back their biological clock by becoming a polyp again.
Aldabra Giant Tortoise
The Aldabra Giant Tortoise is one of the land animals with the longest lifespan. They are of a species of tortoise known as Aldabrachelys gigantea. They are found in Seychelles, East Africa, and are known to possess gene variants that allow gene repair, cancer suppression, and good immune response, thus helping them live long.
Courtesy: Wikipedia
Aldabra Giant Tortoise can live comfortably for hundreds of years. One tortoise of these species holds the record for the longest-living land animal on earth. It was about 192 years old. Aldabra Giant Tortoise were found in almost every part of the world before, but hunting and exploitation led to them becoming extinct in many parts of the world.
Bowhead Whale
This huge sea creature lives in the Arctic. The bowhead whale was discovered hundreds of years ago. It is a species of baleen whale and the only member of the genus Balaena still living on earth. It was recently discovered that they undergo a gene duplication process that helps slow down cell division, helping them live longer.
Courtesy: WWF Arctic
Bowhead whales can live for centuries, with one recently found male being said to be over 200 years old, making them one of the oldest marine mammals. These whales are among the few animals that live in the Arctic all year long and possess hard skulls that can break through 2 feet of ice.
Deep Sea Sponges
Deep sea sponges have existed in the ocean for a long time. Glass sponges, one of the classes of sea sponges, are estimated to have existed for about 10,000 years. They are also known to live for thousands of years. Due to their deep environment, the risk of being killed is lower.
Courtesy: Nautilus Live
Sea sponges are known to have an average lifespan of a few years, but deep sea sponges live for as long as 200 years or more. Sea sponge cells, unlike other animal cells, do not form tissues, and they have the unique ability to regenerate injured or lost parts.
