Agnatha or "jawless fish" once a vertebrate planet's earliest and dominant, appeared millions of years ago in ancient times were dominated by molluscs and arthropods bertentakel spiked.

Currently, the only living example of fishy ancestors were "slime hags" scavenging (which is quite interesting, but not haematophagous) and faced bloodsuckers "lamprey." Many species of lamprey Many memunyai filter for food harmless, but some varieties are famous actually parasites.

Stick to the other fish, they sticking and infiltrate through the meat until they reach the blood or other body fluids, and possibly kill the prey are not strong enough to withstand a lot of fluids or blood loss

Although they seem primitive and savage, lamprey also devoted mother who migrated far to spawn and carefully make a pile of stones to be protective nest their eggs.