How do lampreys and hagfish feed?

1 Answer

Hagfishes and lampreys are believed to form a monophyletic group called the clyclostomes ("circle mouths"). Members of this group of fishes produce an excessive amount of mucus as a defensive measure. While they are virtually blind, they have four pairs of tentacles around their mouths that are used to detect food.

These fish have no jaws, so instead have a tongue-like structure that has barbs on it to tear apart dead organisms and to capture their prey. Hag fish is generally parasitic, known to bore inside large bodied mammals (when injured/dying) or fishes and devour them from inside.

The primary and favorite dish of hagfish and lamprey is polycheate worms.

A lamprey looks like this: