Immortal jellyfish (Turritopsis Dohrnii) is a small-sized jellyfish. It is probably the only animal in the world that can leap back toward its first stage of lifecycle and then return to life again. Thus, it is an amazing survivor. This jellyfish was discovered in the Mediterranean Sea during 1880s.
The body form of this jellyfish is bell-shaped and it has a diameter of 4.5 millimeters. The color of its stomach (called manubrium) is bright red and it is situated at the center of the bell. There are 80 to 90 tentacles along the edges of the bell in adult jellies and only 8 among juveniles.
Immortal jellyfish is widely distributed across the world’s temperate and tropical waters. Originally, this jellyfish belonged to the Pacific. Today, it is found off Japanese waters and the Mediterranean.
This jellyfish becomes mature at about 25 to 30 days when the temperature remains at 20°C.
As the egg of an immortal jellyfish is fertilized, it develops into the first stage of life called larva. The larva of jellyfish is known as planula. When planula settles at the bottom of the sea, it gives rise to a cylindrical-shaped colony of polyps. Within weeks, the polyps are developed into free-swimming jellyfish (medusae). This jellyfish has this remarkable ability to transform itself again into the polyp stage of development. Hence, it is known as immortal.