All About Jawless Fish: History, Evolution and Present Forms
Over 500 million years ago, the first fish evolved. Most of these early fish are now extinct, but a few remain – lampreys and hagfish. These fish look primitive, indeed. They have cartilage instead of bone and a long, eel-like body. They don’t have a jaw bone, but instead, a round, open mouth called an oral disc.
Fun Facts About Jawless Fish for Kids
- Lampreys live in the ocean, as well as freshwater rivers and streams.
- Lampreys start out as eggs and then larva. They live only a short time as adults. They lay eggs and then die.
- Some lampreys are parasites. Their mouths have a strong power of suction like a vacuum. They attach themselves to other fish by their mouths. Then they bore into the fish with their teeth and suck the fish’s blood. Yuck!
- Hagfish secrete mucous-like slime when threatened by a predator. This slime makes the predator gag and back off.
- Hagfish look like eels, but they’re not. They belong to their own ancient family.
- Hagfish eat dead animals. They use their sucking mouth parts to burrow into a carcass.
Jawless Fish Vocabulary
- Primitive: old, simple, uncomplicated
- Cartilage: soft, sinewy material
- Parasites: an animal that attaches itself to a live animal and slowly feeds on that animal
- Bore: drill
- Carcass: the body of a dead animal
Learn More All About Jawless Fish
Watch this awesome video about the Sea Lamprey!
A video documentary of sea lampreys.
Jawless Fish Q&A
Question: Are jawless fish dangerous?
Answer: These fish don’t hurt humans, but they do cause problems sometimes. Lampreys invaded the Great Lakes and nearly destroyed all the native fish populations there.