Image from Wikimedia Commons
Everything has to grow old and die eventually. Cells grow old, they begin to lose their functionality, and they die. When too many cells begin to die, the body begins to malfunction, and the organism dies. This is inevitable and happens to every living organism, right? Well not exactly. Scientists have been discovering that some organisms actually do not age and can indeed live forever. Among these organisms is the hydra.
The hydra is an extremely small (about .25 centimeters in length) aquatic sea animal that can be found in fresh bodies of water. Their bodies consist of five main parts: tentacles, mouth, body, gut cavity, and basal disk. Though many some hydra are brown, most are a green color due to the algae inside of them.
These creatures are carnivorous and eat small organisms such as worms. They have a poison in their tentacles that they fire into prey in order to immobilize them. It then becomes much easier for hydra to get its prey.
One interesting thing about the hydra is that it can actually survive without food for a very long period of time. The algae inside the hydra and the hydra have a mutually beneficial relationship. The algae get a safe environment inside of the hydra and the hydra can survive on the byproducts of the algae. The chloroplasts in the algae are what give the hydra the green color.
So the fact that they do not have to eat makes them immortal? Wrong again.
All the facts work against the hydra. They reproduce immediately after being born and keep reproducing frequently. This should mean that they die very quickly because scientists have found a correlation between reproducing later and more slowly and living longer. This model shows that hydra should only live about a month.
Another factor working against them is their size. Generally, the smaller the organism, the quicker it tends to die. Hydras are tiny. They simply should not live very long at all.
In a study done by Daniel Martinez, hydras managed to live past four years in his lab, before his experiment had to conclude, with no signs of any aging at all. He began to study hydras because he was skeptical about their immortality, but now he is a definite believer.
Why do hydras live forever?
Research has shown that hydras lack senescence, which is the condition of deterioration with age. This means that as they get older, nothing changes with the organism. Another factor believed to increase its lifespan is that it reproduces asexually. When an organism reproduces sexually, it increases its likelihood of death.
The truth is scientists have not figured out what leads to the lack of senescence in hydras. It is a very hot topic in the science community right now because the discovery could lead to a great number things. Though, it would most likely not translate to human immortality, it would definitely help to increase life expectancies, and it could lessen the symptoms off age related deterioration. There could be less pain with aging and that is something worth investigating.