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What is a Lamprey?

J.L. Drede
J.L. Drede

A lamprey is a marine animal that is typically found in coastal and fresh waters. While they are frequently referred to as lamprey eels, they are part of the fish family. A lamprey's most notable feature is its large suction-cup like mouth that is filled with rows of sharp teeth. Most lamprey are parasitic in nature, and survive by attaching mouths to fish and other marine animals. Once attached, they suck the blood out of the host bodies until it dies. There are many different species of the fish, and they can vary in from a 6 to 40 inches (15 to 100 centimeters) in length.

Lampreys are unique fish and they have little in common with most modern day marine life. The only comparable animal to the lamprey is the hagfish, which also resembles an eel and has no real jaw structure. Many scientists have suggested that lampreys are "living fossils," or organisms that have ceased to evolve for millions of years.


This view has not been easy to confirm, since finding fossilized lampreys is difficult as they are mostly made of cartilage that decays quickly after death. The few fossilized specimens that have been found do support this theory, and it appears that for the past 300-plus million years the parasitic marine animals have barely changed at all.

In North America, the sea lamprey is seen as a dangerous pest. Completion of the man made Welland Canal in 1921 saw the species spread from Lake Ontario to the other Great Lakes and quickly become an invasive species. The parasitic marine animal laid waste to fish crops across all the lakes. Entire fisheries were decimated by the lamprey, which had no natural predators in the lakes. The contamination of lampreys was finally controlled in the 1950s, when scientists developed a special chemical agent that killed lampreys while leaving other fish unharmed. Lampreys can still be found in the Great Lakes today, but in much smaller numbers.

In contrast to its negative reputation in America, the lamprey is commonly seen as a delicacy in many other parts of the world, especially Europe. Pie, stew and meat brewet are all foods that can be made using the fish as a primary ingredient. Efforts to recreate the popularity of the marine animal as a food in America have failed to take off. This may have to do with the negative reputation as a parasite, and with its eel-like appearance.

Frequently Asked Questions

What exactly is a lamprey?

A lamprey is an ancient, jawless fish that belongs to the order Petromyzontiformes. Unlike typical fish, lampreys have a funnel-like sucking mouth with rows of sharp, horn-shaped teeth. They are often known for their parasitic species, which attach to other fish to feed on their blood, although some species are non-parasitic and feed on detritus.

How do lampreys feed?

Parasitic lampreys feed by attaching their toothed, funnel-like mouth onto the body of a fish. They secrete an anticoagulant to prevent blood clotting and then consume the host's blood and bodily fluids. Non-parasitic species, on the other hand, typically feed on organic debris and do not attach to hosts.

Are lampreys dangerous to humans?

Lampreys are not directly dangerous to humans as they do not typically attack larger animals. However, they can be a nuisance to commercial fisheries and ecosystems. In the Great Lakes, for example, invasive sea lampreys have caused significant damage to native fish populations, leading to economic and ecological repercussions.

Where can lampreys be found?

Lampreys are found in coastal and fresh waters around the world, particularly in temperate regions. They are anadromous, meaning some species migrate from saltwater to freshwater to spawn. Their distribution spans from the Atlantic and Pacific Oceans to the Great Lakes, where they have been introduced and become invasive.

How do lampreys reproduce?

Lampreys migrate upstream to freshwater rivers and streams to spawn. They do not have paired fins or a swim bladder, so they use their sucker-like mouth to cling to rocks and build nests. After spawning, adult lampreys typically die, and the larvae, known as ammocoetes, will live in the sediment for several years before maturing.

What efforts are being made to control invasive lamprey populations?

Control efforts for invasive lamprey populations, particularly in the Great Lakes, include the use of lampricides, which are chemicals specifically designed to target lamprey larvae without harming most other aquatic species. Additionally, barriers and traps are used to prevent adult lampreys from reaching spawning grounds, and there is ongoing research into biological control methods.

Discussion Comments


Why are these fish so aggressive?


The sea lamprey is native to the Atlantic Ocean which the Great Lakes are connected to. They have become a huge problem in the Great Lakes because the native fish, such as the trout, are in danger of dying out due to the lamprey.

The UMESC (Upper Midwest Environmental Sciences Center) have been working on ways to reduce the number of sea lampreys in the Great Lakes. They tried moving them out but that wasn’t very effective. They are working on chemicals that are designed to kill the sea lampreys without harming the native species. A couple of the chemicals they are working in are TFM and Bayluscide. They are hoping to significantly reduce lamprey reproduction.


@grumpyguppy: Sea lampreys don’t exactly “eat” other fish. As the article stated, they actually suck the body fluids out. They fasten their mouth to the prey and rip out a hole with their rough tongue. Lampreys have a chemical in their saliva that will keep the wound open in the fish until the fish dies. It can keep the wound open for hours or even weeks. Around 1 out of 7 fish that have been attacked by a sea lamprey actually survive.

Now, to your question; Sea lampreys feed on the larger fish. A trout seems to be the favorite but when it comes right down to it, they are not picky eaters.


Do sea lampreys eat any fish or do they have a preference?

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