The Immortal Jellyfish

It seems like stories of people searching for the fountain of youth have been around forever, and as far as animals go there are certainly plenty with much longer life spans than humans. Koi fish have been known to live over 200 years, at least one Aldabra giant tortoise lived to be 255, and a giant barrel sponge in the Caribbean is estimated to be more than 2,300 years old. However, there may be one animal that is indeed impervious to Father Time; Turritopsis nutricula, the immortal jellyfish.

Photo: Peter Schuchert

All jellyfish go through several life cycles. There are born as larvae that settle onto the sea floor or other underwater structure and develop into polyps, which look similar to a tiny octopus with its tentacles pointed up. The jellyfish buds from this polyp and begins its adult life, feeding constantly and growing quite rapidly. After reaching adult size the jellyfish will spawn, usually dying a short time after. The largest jellyfish live 2-6 months, with smaller varieties only living a matter of weeks.

So, how does the tiny (0.18”) immortal jellyfish manage to live on? The answer is a process called transdifferentiation. After the immortal jellyfish spawns as an adult, it uses this process to transform its cells back into that of an immature polyp, dropping to the sea floor and starting its lifecycle all over again. Some animals such as salamanders can use this process to re-grow limbs, but the immortal jellyfish is the only known animal that can apply transdifferentiation to its whole body, meaning that instead of dying, it becomes a newborn again; and it can repeat this process over and over.

Because these jellyfish are immortal, their population is exploding. Once native only to Caribbean waters, they can now be found in oceans all over the world.

A Salute to Space Animals

As you’re probably aware, the Space Shuttle Atlantis made its final launch today, marking an end to the shuttle program and the start of an open-ended hiatus for manned American space flight. As commonplace as shuttle missions now seem, it’s important to remember how many animals blasted off into the unknown and in many cases gave their lives to help advance space programs throughout the world.


Baker, the first monkey to survive space flight.

 The first animals launched into space were fruit flies aboard a United States V2 rocket in 1947 to explore high-altitude radiation exposure, followed just a few years later by a rhesus monkey named Albert II in 1949.



Laika, the first dog to enter orbit.

In 1957, a Russian dog named Laika became the first animal to enter orbit aboard Sputnik 2. Unfortunately, at the time the technology to reenter the atmosphere from orbit did not yet exist, and Laika was unable to survive the mission. She is memorialized by a statue and plaque at the Russian Star City cosmonaut training facility and her likeness has appeared on postage stamps. In 1960, two other Russian dogs named Belka and Strelka became the first animals to enter orbit and return alive on Sputnik 5.

Ham the chimp upon recovery from his mission in 1961.

In 1961, chimpanzees entered the space program when Ham the chimp was launched into space as part of the U.S. Mercury-Redstone 2 mission. Ham was trained to pull levers in flight to receive food, proving that it was possible to perform tasks in space. Later that same year another chimp named Enos became the first chimpanzee to enter orbit.

With manned spaceflight becoming possible in the 1960s, animals became less common on missions. However in the decades since, hundreds of animals from tortoises to mice have taken part in missions as part of scientific studies. Even as recently as May, 2011 spiders were taken into orbit on the final flight of Space Shuttle Endeavor to study the effects of zero gravity on their behavior.




Space Shuttle Endeavour

 Although the future of space exploration is uncertain, we all owe a debt of gratitude to the brave animals that have helped advance technology and our understanding of the universe.

The Wisest Tortoise of Them All

When we think about animals with long life spans, usually large mammals such as horses and elephants come to mind. While it is true that some other animals such as catfish, buzzards, and some lizards can live as long or longer than humans, the true “fountain of youth” animal has got to be the giant tortoise. These huge land-going tortoises, specifically the Galapagos tortoise and the Aldabra giant tortoise, weigh more than 500lbs and can live well in excess of 100 years.

The longest-lived tortoise ever recorded was named Adwaita. Adwaita was born in 1750 in the Seychelles islands, where he was captured by British seafarers and brought to India as a gift to British nobleman General Robert Clive, who kept the tortoise as a pet. Adwaita was transferred to the Alipore zoo in India in 1875, and continued to live there until his passing on March 23rd, 2006. Scientists’ carbon dated Adwaita’s shell and determined that he was 255 years old at the time of his death.

Adwaita in 2005. Photo: AP

Living Shells

The shell of a turtle or tortoise is made up of about 50 bones that are all connected together. This tissue is very much alive, not like dead tissue found in hair or finger nails. Tortoises also have the ability to store sperm, sometimes producing fertile eggs three years after their last mating.

Bonus Fact: The Galapagos tortoise is the largest living tortoise, weighing approximately 570 pounds.

Symbol of the Galapagos Islands

I thought today we’d move way from the Amazon to the Galapagos Islands. Of course, the first animal that comes to mind is the Giant Tortoise. The Giant Tortoise can weigh over 500 pounds and measure 5 to 6 feet long and be 3 feet high. In the 18th and 19th centuries these land tortoises were almost hunted to extinction by sailors killing them for their meat.

Galapagos tortoises vary in shape. The tortoises with flat or saddle-shaped carapaces (shells) live on the coastal lands. They eat leaves from low-branched trees and shrubs. The highland tortoises have larger, dome-shaped shells and feed on plants, grasses, and fallen fruit. A favorite food is the Manzanillo fruit (or poison apple). If a person eats a few, it’s deadly!