THE ANIMAL FILES

Beluga whale

Delphinapterus leucas

A beluga can turn its head without turning its whole body.

Adult belugas are recognisably pale, but calves begin life grey. Their rounded forehead contains an acoustic organ called the melon, and their unfused neck vertebrae permit unusual head mobility for a whale. These features make its familiar outline a useful introduction to underwater sensing and movement.[1]

Follow the evidence ↓
Beluga whale
Image: Carquinyol from Badalona, Catalunya · Commons · CC BY-SA 2.0
Young colour
Calves are grey rather than adult white[1]
Forehead
A fatty melon participates in echolocation[1]
Back outline
A dorsal ridge rather than a dorsal fin[1]

White arrives with age

Calves are grey and gradually lose pigmentation as they mature. Adult whiteness should therefore not be used as a requirement for recognising a young beluga. The skin also undergoes seasonal shedding; animals in summer estuaries may rub against gravel. Colour and skin appearance reflect life stage and season, rather than one permanently pristine white surface.[1]

A movable head and an acoustic forehead

The seven neck vertebrae are not fused together, allowing lateral head movement. In front, the prominent melon contains fatty tissue and changes shape during sound production. It is associated with echolocation, not an enlarged exposed brain. Teeth hold prey rather than grinding it in the way human chewing teeth do.[1]

Steering without a tall dorsal fin

The small, rounded pectoral flippers help steer and manoeuvre, while tail movements provide propulsion. A ridge replaces the dorsal fin on the back. Under-ice movement and heat conservation have been proposed as explanations for this shape.[1]

A COMMON MIX-UP

Is a grey calf necessarily a different whale species?

No. Beluga calves are grey and become pale as they mature.[1]

TRY A LITTLE REASONING

How can an unfused neck help a beluga inspect something beside it?

Reveal the explanation

The head can turn laterally without requiring the entire body to rotate.[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 — Delphinapterus leucas (adapted and translated; exact revision)
  2. NCBI Taxonomy — Delphinapterus leucas (identity and game lineage)

Last fact check:

One discovery leads to another

NarwhalThe famous spiral is a tooth, not a horn.Monodon monoceros ↗OrcaDifferent orca communities can share an ocean without sharing a menu.Orcinus orca ↗Common bottlenose dolphinAn echo helps find an object; a whistle helps keep contact.Tursiops truncatus ↗