10 Weird Lamprey Facts: Types and Species

When we think of “living fossils,” we often imagine the Coelacanth or the Horseshoe Crab. Yet, lurking in our rivers and oceans is a creature far older and more bizarre: the Lamprey. These eel-like vertebrates have haunted Earth’s waters for over 360 million years, surviving four mass extinctions and outlasting the dinosaurs.

Belonging to the class Petromyzontida, lampreys are jawless, boneless, and primitive, yet they are some of the most successful survivors in evolutionary history. This guide dives deep into the world of lampreys, from the giant sea-dwelling parasites to the tiny brook dwellers.

Lampreys Key Facts

The Anatomy of an Alien: What Makes a Lamprey?

To understand a lamprey, you must first set aside everything you know about “normal” fish. They are not eels, though they look like them; they are a unique branch of the vertebrate tree.

The Circular Mouth (The Oral Disc)

The most famous feature of the lamprey is its mouth. Lacking a jaw, they possess a circular, funnel-like suction cup lined with concentric rows of horn-like teeth. In parasitic species, the center contains a sharp, rasping tongue used to bore through the scales and skin of other fish to reach their blood and fluids.

Unique Sensory Organs

• Four Eyes: Lampreys possess two standard eyes, but they also have two light-sensing parietal eyes on top of their heads. These “third and fourth eyes” help them sense light changes even when buried in silt.
• The Single Nostril: Unlike most vertebrates with paired nostrils, the lamprey has a single, central nostril located right on top of its head.
• Seven Gill Pores: Because parasitic lampreys spend their time attached to prey with their mouths, they cannot breathe like normal fish. Instead, they have seven distinct gill pores on each side of their body that “pump” water in and out independently of the mouth.

Detailed Profiles of Lamprey Species

The lamprey is one of the most primitive vertebrates alive today. Often called “living fossils,” these jawless, eel-shaped fish have remained largely unchanged for over 360 million years. They are broadly categorized into parasitic and non-parasitic types, with about 38 species recognized worldwide.

Parasitic Lampreys

These species are the most famous—or infamous—due to their “vampiric” feeding habits. As adults, they attach to other fish to feed on their blood and bodily fluids.

Sea Lamprey (Petromyzon marinus)

The largest of all species, reaching up to 120 cm. They are anadromous, living in the ocean but migrating to freshwater to spawn.

• Impact: In the North American Great Lakes, they are a devastating invasive species. A single individual can kill up to 40 pounds of fish in its lifetime.
• Anatomy: They possess a large oral disc filled with sharp, keratinous teeth and a rasping tongue.

Pacific Lamprey (Entosphenus tridentatus)

Native to the North Pacific, these are ecologically and culturally vital to Indigenous tribes in the Pacific Northwest.

• Feat: They are incredible climbers. Using their suction-cup mouths, they can scale vertical rock faces and waterfalls to reach upstream spawning grounds.

European River Lamprey (Lampetra fluviatilis)

Smaller than the sea lamprey (around 30–50 cm), they inhabit coastal waters and rivers across Europe. Historically, they were a prized delicacy for royalty.

Non-Parasitic Lampreys

Many species, particularly those in the “Brook Lamprey” group, never feed as adults.

American Brook Lamprey (Lethenteron appendix)

These lampreys spend most of their lives (3–7 years) as eyeless, mud-dwelling larvae called ammocoetes.

• Adult Stage: Once they transform into adults, their digestive tract becomes non-functional. They do not eat; they simply spawn and die within a few weeks.
• Size: They are much smaller than parasitic types, usually topping out at 15–20 cm.

The Strange Life Cycle: From Ammocoete to Adult

The lamprey’s life begins in a way that looks nothing like its adult form.

The Larval Stage (Ammocoetes)

After hatching in a freshwater nest, lampreys begin life as eyeless, toothless larvae called ammocoetes. They look so different from adults that early scientists thought they were a completely different animal.

• Burrowing: They live in riverbeds, buried in the mud for 3 to 6 years.
• Filter Feeding: Instead of blood, they eat algae and organic debris filtered from the water.

Metamorphosis

When it is time, the ammocoete undergoes a radical transformation. It develops eyes, a silver belly, and its terrifying circular mouth. Once the transformation is complete, the parasitic species head to open water to begin their “vampire” phase, while non-parasitic species prepare to spawn and die.

Extreme Biology: Chromosomes and “Stone-Sucking”

Lampreys hold several biological records that baffle geneticists.

• Extreme Chromosomes: While humans have 46 chromosomes, lampreys have one of the highest counts of any vertebrate, ranging from 164 to 174.
• The “Stone Sucker”: Their name comes from the Latin lampetra, which means “stone-licker.” This refers to their habit of using their suction mouths to move large stones to build nests (called “redds”) in riverbeds.
• No Bones: Like sharks and rays, lampreys have a skeleton made entirely of cartilage. They have a “notochord” (a primitive spinal rod) rather than a bony spine.

The Lamprey’s Role in the World Today

Today, the lamprey is a creature of duality. In some places, they are a protected, ancient species struggling with habitat loss and dam construction. In others, they are an invasive nightmare that requires millions of dollars in management.

Environmental Indicators

Because lampreys spend so much time as larvae in the mud, they are highly sensitive to pollution. If a river has a healthy population of brook lampreys, it is usually a sign that the ecosystem is thriving.

Human Interaction

While they look frightening, lampreys do not hunt humans. They are cold-blooded specialists. However, their impact on commercial fishing in the Great Lakes remains a serious economic concern. Scientists use pheromones and specialized barriers to manage their populations without harming other fish.

Summary of Amazing Lamprey Facts

1. Ancient Survivors: Lampreys have existed for over 360 million years and survived four mass extinctions.
2. Jawless Fish: They lack jaws, bones, and paired fins, belonging to the class Petromyzontida.
3. Four Eyes: In addition to two normal eyes, they have two light‑sensing parietal eyes on top of their heads.
4. Unique Breathing: They breathe through seven gill pores on each side, not through their mouths.
5. Only One Nostril: A single central nostril sits atop their heads.
6. Extreme Chromosomes: They have one of the highest vertebrate chromosome counts (164–174).
7. Circular Mouth: Their toothed oral disc acts like a suction cup to attach to prey.
8. Massive Appetite: A single sea lamprey can kill about 40 pounds of fish in its lifetime.
9. “Stone Sucker”: The name lamprey comes from Latin lampetra, meaning “stone‑licker.”
10. Long Larval Stage: Eyeless larvae (ammocoetes) burrow in riverbeds for 3–6 years before metamorphosis.
11. Parasitic Adults: Many species feed on fish blood and fluids, while others are non‑feeding or carnivorous.
12. Migratory Behavior: Some species migrate from saltwater to freshwater to spawn.
13. Gill Pouches: They breathe through seven pairs of gill openings, visible as small pores.
14. Size Range: Species vary from tiny brook lampreys (15 cm) to giant sea lampreys (120 cm).
15. Edible Delicacy: Despite their appearance, lampreys are eaten in Finland, Sweden, Japan, and historically prized in Europe.

Summary

A lamprey is a primitive, jawless fish that looks like an eel but belongs to a completely different evolutionary lineage. Having existed for over 360 million years, they are often called “living fossils.” They are defined by their cartilaginous skeletons, lack of scales, and a signature circular, tooth-lined mouth used for suction.

While some are famous as “vampires” of the sea, many species are harmless to other fish and play vital roles in the health of freshwater ecosystems.

Frequently Asked Questions About Lampreys

Do lampreys attack humans?

No. Lampreys are not interested in humans. They are cold-blooded specialists evolved to feed on other fish. While a lamprey might accidentally latch onto a swimmer if it confuses them for a host, they cannot survive on human blood and will generally let go immediately.

What is the difference between a lamprey and an eel?

Though they share a long, slender body shape, they are not related. Eels are “bony fish” with jaws, scales, and paired fins. Lampreys lack jaws, have a skeleton made of cartilage (like a shark), and have no paired fins or scales.

Why are they called “Stone Suckers”?

Their name comes from the Latin lampetra, meaning “stone-licker.” This is because lampreys use their suction-cup mouths to grab and move stones to build nests, called redds, on the riverbed.

Are all lampreys parasites?

Actually, no. About half of the 38 known species are non-parasitic. These species (like the Brook Lamprey) live for years as larvae, but once they turn into adults, they stop eating entirely. They simply spawn and die within a few weeks.

Can you eat lampreys?

Yes. They have been a delicacy in Europe for centuries and are still popular in countries like Finland, Sweden, and Japan. They are described as having a very “meaty” texture, more like beef than fish.

Why are they a problem in the Great Lakes?

The Sea Lamprey is an invasive species in the North American Great Lakes. Because they had no natural predators there when they arrived, their population exploded, and they began killing off native trout and whitefish at an alarming rate. One sea lamprey can kill up to 40 pounds of fish in its lifetime.

Taniya

94% of pet owners say their animal pal makes them smile more than once a day. In 2007, I realized that I was made for saving Animals. My father is a Vet, and I think every pet deserves one. I started this blog, “InPetCare”, in 2019 with my father to enlighten a wider audience.