Top Ten ‘Immortal’ Animals

Top Ten ‘Immortal’ Animals


  1. Immortal Jellyfish
    The wonder of nature itself, the Turritopsis nutricula jellyfish left the scientific community speechless once it was discovered that it can cycle itself back to the immature polyp stage once it has reached the mature adult life stage. What this basically means is that in a way it never gets old and can therefore live forever. The secret this animal holds might be one of the ultimate goals that many try to reach. Therefore, it is not surprising that numerous experiments and researches are to be conducted in the near future.
  2. Hydra
    Hydra is a genus of small, simple, fresh-water animals that possess radial symmetry. Hydra are predatory animals belonging to the phylum Cnidaria and the class Hydrozoa. They can be found in most unpolluted fresh-water ponds, lakes, and streams in the temperate and tropical regions and can be found by gently sweeping a collecting net through weedy areas. They are multicellular organisms which are usually a few millimeters long and are best studied with a microscope. Biologists are especially interested in Hydra due to their regenerative ability; and that they appear not to age or to die of old age. This discovery was first reported by Daniel Martinez, in a 1998 article in Experimental Gerontology, which stated that Hydra are biologically immortal. In 2010 Preston Estep published (also in Experimental Gerontology) a letter to the editor arguing that the Martinez data support rather than refute the hypothesis that Hydra senesce. The controversial unlimited life span of Hydra has attracted the attention of natural scientists for a long time. Hydra stem cells have a capacity for indefinite self-renewal. The transcription factor, “forkhead box O” (FoxO) has been identified as a critical driver of the continuous self-renewal of Hydra. A drastically reduced population growth resulted from FoxO down-regulation, so research findings do contribute to both a confirmation and an understanding of Hydra immortality. While Hydra immortality is well-supported today, the implications for human aging are still controversial. There is much optimism; however, it appears that researchers still have a long way to go before they are able to understand how the results of their work might apply to the reduction or elimination of human senescence.
  3. Antarctic Sponge (1,550+)
    Located in the freezing waters of Antarctic Ocean, the immobile Antarctic sponge grows very slow. This also makes it able to last for centuries, as the oldest known specimens are over 1,550 years old.
  4. Ocean Quahog (507+)
    The “ocean quahog,” Arctica islandica, which, although superficially similar in shape to traditional clams, is in a different family of bivalves: it is rounder than the hard clam, usually has black periostracum, and there is no pallial sinus in the interior of the shell. They have been known to live up to 500 years. In 2006 a Quahog clam was taken from the ocean floor at the north coast of Iceland. It was later confirmed to be 507 years old and is recognized as the world’s longest lived non-colonial animal.
  5. Aldabara Giant Tortoise (255+)
    The Aldabra giant tortoise (Aldabrachelys gigantea), from the islands of the Aldabra Atoll in the Seychelles, is one of the largest tortoises in the world. Aldabra giant tortoises are exactly what they sound like– freaking giant. The males can weigh nearly 800 pounds and scientists aren’t sure just how long Aldabra tortoises live, because they have a tendency to live longer than the people watching them. The oldest confirmed age of an Aldabra tortoise was 255 years, but some may have lived to be twice that age.
  6. Koi Fish (226+)
    Koi fish,”brocaded carp,” are ornamental varieties of domesticated common carp (Cyprinus carpio) that are kept for decorative purposes in outdoor koi ponds or water gardens. Koi varieties are distinguished by coloration, patterning, and scalation. Some of the major colors are white, black, red, yellow, blue, and cream. The most popular category of koi is the Gosanke, which is made up of the Kohaku, Taisho Sanshoku, and Showa Sanshoku varieties. Although most Koi typically have a lifespan of 47 years, one notable Koi named Hanako amazed the scientific community with it’s stunning lifespan of 226 years.
  7. Bowhead Whale (211+)
    The bowhead whale (Balaena mysticetus) is a baleen whale of the right whale family Balaenidae, in suborder Mysticeti and genus Balaena. A stocky dark-colored whale without a dorsal fin, it can grow to 20 m (66 ft.) in length. This thick-bodied species can weigh 74 long tons; to 100 98 long tons, second only to the blue whale, although the bowhead’s maximum length is less than several other whales. It lives entirely in fertile Arctic and sub-Arctic waters, unlike other whales that migrate to feed or reproduce to low latitude waters. It was also known as Greenland right whale or Arctic whale. American whalemen called it the steeple-top, polar whale, or Russia or Russian whale. The bowhead has the largest mouth of any animal. The bowhead was an early whaling target. Its population was severely reduced before a 1966 moratorium. The population is estimated to be over 24,900 worldwide, down from an estimated 50,000 before whaling.
    Links: Top Ten Largest Animals,,
  8. Red Sea Urchin (200+)
    Strongylocentrotus franciscanus, commonly called the red sea urchin (although its color ranges from pink or orange to nearly black), is a sea urchin found in the Pacific Ocean from Alaska to Baja California. It lives in shallow waters from the low-tide line to 90 m (300 ft.) deep, and is typically found on rocky shores that are sheltered from extreme wave action.
  9. Lobster (200+)
    Lobsters have somehow figured out a way to defy aging as we know it. Unlike people, lobsters don’t experience any change in metabolism or body-function as they get older. A one-hundred-year-old lobster will continue eating, moving and mating. This longevity may be due to telomerase, an enzyme that repairs DNA sequences of the form “TTAGGG”. Lobsters express telomerase as adults through most tissue, which has been suggested to be related to their longevity. This sequence, repeated hundreds of times, occurs at the ends of chromosomes and are referred to as telomeres.They also keep getting growing, which means that after a couple-hundred years, they can grow to the size of a large wolf. The largest recorded lobster is believed to have weighed 51 and a half pounds and reached 50 and a half inches long from tail to claws.
    Links: Top Ten Crabs/Lobsters,,,
  10. Rougheye Rockfish (205+)

    The rougheye rockfish is a rockfish of the genus Sebastes. It grows up to 97 cm (38 in) in length, with the IGFA record weight being 14 lb 12 oz (6.7 kg). Similar to many other members of its genus, it is extremely long-lived, and has been known to reach an age of 205 years. Rougheye rockfish are deepwater fish, and exist between 31° and 66° latitude, in the North Pacific, and specifically along Japan to the Navarin Canyon in the Bering Sea, to the Aleutian Islands, all the way south to San Diego, California, at depths of between 25 and 900 m (82 and 2,953 ft.).
    Links: Top 100 Fish,,
  11. Humans ?
    23Rajasthan old man portrait4
    With advances in science, the longevity of human beings is beginning to be better understood, allowing us with the opportunity to live longer and healthier lives. In the short term, this seemingly evolutionary breakthrough will meet with systematic challenges unless we can figure out a peaceful solution to our population growth and resource management.
    Links: People, Top Ten Oldest Humans, 100 Evolutionary Humans,
  12. Sea Anemone (80+)

    Though the sea anemone doesn’t look like an immortal animal, or even an animal for that matter, it doesn’t age as it gets older, it simply grows bigger. In between swaying to the left, swaying to the right, and occasionally swallowing a bit of debris, this ‘brainless’ polyp is busy defying everything we know about mortality. Fortunately for those who find this a little creepy, none of them have lived long enough to develop sentience yet, they usually get wiped out at around age 80 by heat, water pollution, infections and greedy collectors.

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