Lampreys (Petromyzontiformes) are jawless vertebrates most closely related to hagfish (Myxiniformes). Together, they form the only surviving groups of ancient agnathans (jawless fish).
5 in - 3 ft. (13 cm - 1 m)
Length
1 -5 lbs (0.5-2.3 kg)
Weight
About
The Lamprey (order Petromyzontiformes) is an ancient, jawless fish belonging to the family Petromyzontidae, with a lineage dating back over 360 million years. Found in temperate freshwater and coastal seas of the Northern Hemisphere, lampreys are often described as “living fossils,” retaining many primitive traits that reveal much about early vertebrate evolution.
Lampreys are eel-like in shape, typically ranging from 5 to 40 inches (13–100 cm) depending on the species. They lack jaws, paired fins, and scales, distinguishing them from most modern fish. Instead, they possess a round, sucker-like mouth lined with concentric rows of sharp keratinized teeth and a rasping tongue. This unique oral disc allows parasitic species to latch onto host fish, bore into their flesh, and feed on blood and bodily fluids. Non-parasitic species, however, live as filter-feeding larvae before maturing and reproducing without feeding further.
The life cycle of lampreys is remarkable. They begin as blind, worm-like larvae (ammocoetes), living buried in sediment for several years and filtering microscopic food. After metamorphosis, some species become parasitic and migrate to lakes or the ocean to feed, while others transition directly into reproductive adults. All lampreys are semelparous, meaning they spawn once in rivers or streams before dying. Females may lay tens of thousands of eggs in gravel nests, ensuring the continuation of the species.
Ecologically, lampreys are both fascinating and controversial. In their native ranges, they play important roles in aquatic food webs. However, invasive populations—such as sea lampreys (Petromyzon marinus) in the North American Great Lakes—have caused severe declines in native fish populations, prompting large-scale control efforts.
Culturally, lampreys have been eaten since medieval times, once considered a delicacy in Europe. Today, they are studied as models for vertebrate evolution, regeneration, and neuroscience.
With their ancient lineage, unusual anatomy, and ecological impact, lampreys remain among the most extraordinary and enigmatic of all fishes.
Threatened:
Extinct
Critically Endangered
Endangered
Vulnerable
Near Threatened
Least Concern
Physical Characteristics
Lampreys (Petromyzontiformes) are jawless, eel-like fish considered among the most primitive vertebrates, with distinctive features that set them apart from modern fish:
Body: They have elongated, cylindrical, eel-like bodies lacking paired fins and scales. Their smooth, cartilaginous structure makes them flexible swimmers.
Head and Mouth: Lampreys lack true jaws. Instead, they possess a circular, sucker-like oral disc lined with sharp keratinized teeth and a rasping tongue, used to latch onto host fish and feed on blood or bodily fluids.
Fins: They have two dorsal fins and a single caudal (tail) fin. Unlike most fish, they lack pectoral and pelvic fins, giving them a primitive body plan.
Eyes: Well-developed lateral eyes provide vision, while some species also have a pineal eye on the top of the head that detects light.
Coloration: Lampreys are typically grayish-brown to olive on the back with lighter undersides, blending with riverbeds or ocean floors. Some species darken when parasitic feeding begins.
Size:
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Length: Species range from 5 in (13 cm) brook lampreys to over 3 ft (1 m) sea lampreys.
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Weight: Most weigh under 1 lb (0.5 kg), though large species can reach 2–5 lbs (1–2.3 kg).
Adaptations: Their sucker-like mouths, scaleless bodies, and lack of jaws mark them as evolutionary relics. Many are parasitic, while others feed only in larval stages before metamorphosis.
Reproduction
Lampreys have a unique reproductive cycle that is tied to freshwater spawning runs, often compared to salmon:
1. Mating and Courtship:
Adults migrate from the ocean or large lakes into rivers and streams to spawn, typically in spring and early summer. Males and females work together to construct shallow nests (redds) by moving stones with their mouths.
2. Spawning:
Fertilization is external. Females release thousands of eggs into the nest while males release sperm simultaneously. Spawning is often accompanied by twisting and writhing motions to ensure egg placement.
3. Eggs:
Eggs are adhesive, sticking to gravel and stones in the nest. Incubation lasts 2 to 3 weeks, depending on water temperature.
4. Larval Stage (Ammocoetes):
After hatching, larvae drift downstream and burrow into soft sediment. They remain filter-feeding as ammocoetes for 3 to 7 years, consuming algae, detritus, and microscopic organisms.
5. Metamorphosis:
Larvae undergo a dramatic transformation, developing eyes, a sucker-like mouth, and teeth. Depending on the species, they either become parasitic adults that attach to host fish or non-parasitic adults that do not feed.
6. Sexual Maturity:
After metamorphosis, adults live for 1 to 2 years. They reproduce once (semelparous strategy) and die shortly after spawning.
Lampreys’ extended larval stage, single reproductive event, and primitive spawning habits make their life cycle one of the most unusual among vertebrates.
Lifespan
Lampreys, among the most primitive vertebrates, have unusual lifespans shaped by long larval stages and short adult lives.
Lifespan in the Wild:
Most lampreys live 6 to 10 years, though the majority of this time is spent as larvae (ammocoetes) burrowed in river sediments. The larval stage lasts 3 to 7 years, followed by metamorphosis into adulthood. Adults typically survive only 1 to 2 years, with many dying shortly after spawning.
Lifespan in Captivity:
Lampreys are rarely kept in captivity due to their specialized life cycle and diet. In laboratory or research settings, larval lampreys may survive several years, but adults generally live less than 2 years after transformation.
Threats to the Lamprey:
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Habitat Degradation: Dam construction and sediment disruption hinder spawning migrations and larval habitats.
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Pollution: Contaminated waters reduce larval survival rates.
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Overpopulation (Invasive Species): In places like the Great Lakes, invasive sea lampreys disrupt native fish populations, prompting human control measures.
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Predation: Eggs and larvae are vulnerable to fish, birds, and invertebrates.
Lampreys’ unusual balance of long larval development and short adult lives highlights their unique and ancient evolutionary strategy.
Eating Habits
Lampreys exhibit very different feeding strategies depending on life stage and species:
Diet:
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Larvae (Ammocoetes): Filter-feed on algae, detritus, and microscopic organisms while buried in sediment.
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Parasitic Adults (e.g., Sea Lamprey): Feed on blood and bodily fluids of host fish, using their rasping tongues and keratinized teeth.
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Non-Parasitic Adults (e.g., Brook Lamprey): Do not feed as adults, living off stored energy reserves until spawning.
Hunting Strategy:
Parasitic adults attach to host fish with their sucker-like mouths. They rasp through scales and skin, secreting anticoagulants to keep blood flowing as they feed.
Feeding Mechanism:
Their circular oral disc creates suction, while rows of sharp keratinized teeth anchor them to hosts. The rasping tongue scrapes tissue and opens wounds to access fluids.
Foraging Behavior:
Parasitic lampreys are opportunistic, attaching to a wide variety of fish species, sometimes causing serious injuries or death. Non-parasitic lampreys focus all energy on reproduction instead of feeding.
Ecological Role:
Parasitic lampreys regulate fish populations, though invasive species (like sea lamprey in the Great Lakes) can devastate native fisheries. Non-parasitic species contribute as larvae, recycling nutrients in sediments.
Feeding Limitations:
Since parasitic lampreys rely entirely on host fish, their survival is closely linked to host abundance. Non-parasitic species face adult starvation after metamorphosis.
Lampreys’ sucker-feeding adaptations and contrast between parasitic and non-parasitic strategies make them one of the most unusual feeders in aquatic ecosystems.
Uniqueness
Lampreys are among the most ancient and unusual vertebrates, with traits that make them stand out in the animal kingdom:
Jawless Design: Unlike most fish, lampreys lack jaws and paired fins, retaining a primitive body plan that dates back over 360 million years.
Sucker-Like Mouth: Their circular oral disc, lined with keratinized teeth and a rasping tongue, allows them to attach to hosts and feed on blood and tissue.
Parasitic and Non-Parasitic Forms: Some species are parasitic as adults, while others do not feed at all after metamorphosis, surviving only long enough to spawn.
Eye Migration: Like many primitive vertebrates, they undergo dramatic changes during metamorphosis, developing well-formed eyes and feeding structures after years as blind, filter-feeding larvae.
Semelparous Life Cycle: Lampreys spawn once and die shortly after, investing all adult energy into reproduction.
Ecological Impact: While native lampreys are important for nutrient cycling and population control, invasive sea lampreys in the Great Lakes have caused massive declines in commercial fish populations.
Lampreys’ blend of ancient anatomy, unusual feeding strategies, and dramatic life cycle makes them one of the most unique and fascinating fish in the world.
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FAQ’s
1. What species is closest to the lamprey?
2. How does the lamprey compare to other species in the same family?
Parasitic species, such as sea lampreys, attach to fish and feed on blood, while non-parasitic species, like brook lampreys, do not feed as adults and live shorter adult lives.
3. What national parks provide the best opportunities to see a lamprey?
Lampreys can be observed in U.S. Pacific Northwest parks such as Olympic National Park (Washington) and Redwood National and State Parks (California), where they migrate upstream to spawn.
4. In what parts of the world can you find lampreys?
Lampreys are found in temperate waters of North America, Europe, Asia, and parts of South America. They inhabit both coastal oceans and freshwater rivers and streams.
5. How many types of lampreys are there?
There are about 40 recognized lamprey species worldwide, divided between parasitic and non-parasitic forms, each with unique life cycles and ecological roles.
