THE ANIMAL FILES

Sea lamprey

Petromyzon marinus

A filter-feeding youngster becomes a fish-attaching adult.

Sea lampreys change feeding method and habitat as they develop, from sediment-dwelling filter-feeding larvae to a jawless attachment-feeding stage.[1]

Follow the evidence ↓
Sea lamprey
Image: Fernando Losada Rodríguez · Commons · CC BY-SA 4.0
A mouth without jaws
A round attaching disc[1]
Life in the sediment
Larvae filter-feed[1]
Back toward spawning streams
Migration links larger waters and rivers[1]

A mouth without jaws

The elongated body lacks paired fins and ends in a circular, sucker-like mouth. Teeth and a rasping tongue help the feeding stage attach to and work against a fish’s surface.[1]

Life in the sediment

Larvae burrow into sand and silt in quieter stream water and feed on suspended material and detritus. This differs from the later attachment-based feeding stage.[1]

Back toward spawning streams

Lake or sea feeding habitats connect with upstream spawning streams. Eggs are placed in bottom nests, and adults die after spawning. Larvae live downstream in quieter sediment.[1]

A COMMON MIX-UP

Does the larva already feed like the attaching adult?

No. The larva filters material while buried in sediment. Metamorphosis changes its feeding structures and behaviour.[1]

TRY A LITTLE REASONING

Why would protecting only adult feeding water leave out part of the lifecycle?

Reveal the explanation

Spawning occurs in streams and larvae use quieter sediment habitats. The adult feeding area does not supply every place required by earlier stages.[1]

Sources & editorial notes

Adapted and translated from the cited Wikipedia revisions, with source-linked reasoning. Image credit and licence are listed separately above.

Adapted and translated from Wikipedia contributors; exact revisions are linked below. CC BY-SA 4.0

  1. Wikipedia contributors — Sea lamprey (cited revision)
  2. NCBI Taxonomy — Petromyzon marinus

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