It's a prehistoric animal that has not changed for 500 million years. When evolution had not invented the mandible as we know it today. It is a euryhaline organism. This means that animals are able to live in a wide range of salt concentrations without altering its metabolism. And so are found in rivers, lakes and seas. In fact, the Lamprey was born in a river, and return to spawn as salmon do.
But nothing Lamprey resemblance to a salmon. The lamprey is parasitic, not predatory, also thanks to its suction mouth is able to cling to the stone to help up the torrents of the rivers. In fact, they are so different that taxonomically speaking not considered fish, being so peculiar, have their own group, the paraphyletic group of cyclostomes.
But go to the outlandish. The mouth of the Lamprey, mouth-suction cup that reminds an alien movie, devoid of jaw. This has the shape of a funnel trimmed teeth and tongue corneal scraping. Attaches to the skin of its host and once hooked up to suck and suck, there has been the case, to kill her.
When the lamprey is a larva, feeds on a different form, has no teeth that we see in adults, nor have eyes. They feed by hairs (called barbules) that filter food. When adults go to sea, living as deep as 500 meters. They reach weights of 1 kg and 1 meter in length (40 inch), then return to spawn in the river, which left between 50,000 and 200,000 eggs ... Those are a lot of eggs ... Then lampreys die as do salmon.
It is very common in the North Atlantic and the Mediterranean Sea, where this animal is conceived as a tasty snack and a part as an essential ingredient in recipes in culinary traditions as old as the Roman.