Planaria are free-living flatworms in the Turbellaria class of the Phylum Plathelminthes that are found all over the world. They primarily live in salt or fresh water lakes, but can also be found in marine and moist terrestrial habitats.

Planaria are an extremely unique species unlike any other known.  Instead of eyes, they have eyespots which allow them to sense light and instead of a stomach, they have a pharynx which not only allows them to eliminate waste, but also ingest and digest food in the same place.

Planaria can eat almost anything, even tiny bits of themselves.

What is most unique about these tiny animals is their ability to regenerate individual whole planaria after having any part of their bodies amputated.  It is a well-known fact that geckos will regrow their tails if they are cut off, but planaria are superior to geckos in that they are able to essentially reproduce by being cut in half.

In fact, planaria can be cut in more than 250 pieces and each piece will regenerate, or clone, into a brand new planaria with all necessary organs, including a brain.

Planaria are divided into two different basic types: sexual and asexual. The sexual planarian will mate and produce eggs while the asexual will fission, or rip, themselves apart to create new planaria.

Researchers have been trying to figure out the planaria’s mysterious ability to survive being cut in to tiny pieces, as this would kill any other species.

The first known recognition of planaria and their regenerative properties was noted by Peter Simon Pallas in 1766. Since then, numerous studies have been done on planaria attempting to discover their secret to leading immortal lives.