Feeding:
* No Jaws: As the name suggests, these fish lack jaws. This means they cannot chew or tear food.
* Suction Feeding: They have a circular mouth that opens wide and creates suction, allowing them to suck up small prey like worms, crustaceans, and other fish.
* Teeth-like structures: They have rows of tooth-like structures in their mouths, called keratinized plates, which help them scrape food from surfaces or hold onto prey. These aren't true teeth as they are not made of dentin.
Body Structure:
* Cartilaginous Skeleton: Their skeleton is made of cartilage, which is lighter and more flexible than bone, making them more maneuverable in the water.
* Slender Body: They typically have an elongated, snake-like body which helps them navigate through tight spaces and burrows.
* Lateral Line System: A system of sensory canals along their body allows them to detect vibrations in the water, helping them find prey and avoid predators.
Other Adaptations:
* Gill Openings: They have several gill openings on the sides of their body, instead of a single operculum like bony fish.
* No Scales: Most jawless fish lack scales, instead having a slimy skin that offers protection and helps them move through the water more easily.
* Parasitism: Some jawless fish, like lampreys, are parasitic and attach themselves to other fish, feeding off their blood.
Examples of Jawless Fish:
* Lampreys: Parasitic fish with a sucker-like mouth and sharp teeth that attach to other fish.
* Hagfish: Slime-producing scavengers that feed on dead or dying fish.
These adaptations have allowed jawless fish to thrive in diverse aquatic environments and are a testament to their evolutionary success.