THE ANIMAL FILES

Yellow-bellied sea snake

Hydrophis platurus

An ocean home does not mean drinking the ocean.

The yellow-bellied sea snake carries a strongly aquatic design: a compressed body, small belly scales and a paddle-like tail.[1]

Follow the evidence ↓
Yellow-bellied sea snake
Image: Aloaiza · Commons · CC BY 3.0
A swimming body
The tail is flattened into a paddle.[1]
Fresh water at sea
Rain can create a surface freshwater lens.[1]
Hunting at the surface
Floating snakes can capture approaching fish.[1]

A swimming body

A laterally compressed body and flattened tail suit movement through water. Belly scales are much smaller than those of many land snakes, and movement on land is poor.[1]

Fresh water at sea

This snake drinks fresh or sufficiently dilute water. Rain-generated surface lenses have been proposed as an important supply: temporary layers less salty than the seawater below.[1]

Hunting at the surface

Small pelagic fish may approach a floating snake as shelter. The snake can then move backwards and lunge with its jaws. Surface drift lines also gather snakes in aggregations; a feeding advantage has been proposed, rather than demonstrated as the sole explanation for every gathering.[1]

A COMMON MIX-UP

Does living in seawater prove that a snake drinks it?

No. Habitat and drinking water are separate questions; this species relies on fresh or sufficiently dilute water.[1]

TRY A LITTLE REASONING

How could heavy rain help a snake far from a river mouth?

Reveal the explanation

Rain can create a less salty surface layer. That offers a possible drinking opportunity without a journey onto land.[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 — Yellow-bellied sea snake (cited revision)
  2. NCBI Taxonomy — Hydrophis platurus

Last fact check:

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