THE ANIMAL FILES

Narwhal

Monodon monoceros

The famous spiral is a tooth, not a horn.

The narwhal's tusk projects from the upper jaw and is usually conspicuous in males. Most females lack an erupted tusk, yet feed successfully on fish and squid. Clicks help locate prey and obstacles in Arctic waters.[1]

Follow the evidence ↓
Narwhal
Image: пресс-служба ПАО "Газпром нефть" · Commons · CC BY-SA 4.0
A canine, not a horn
The tusk is an elongated upper canine.[1]
Several tusk roles
Tusk functions include signalling and documented food handling.[1]
Finding and taking prey
Fish and squid occur in stomach records.[1]

A canine, not a horn

Usually the left canine erupts into the long spiral. Some males develop two visible tusks, while females rarely have an erupted one.[1]

Several tusk roles

Sexual signalling is an important interpretation of the tusk. It also contains sensory nerves, and drone footage documented tapping small fish. These observations do not make the tusk essential for every meal, particularly in untusked females.[1]

Finding and taking prey

Arctic cod, Greenland halibut and squid feature in diet studies. Suction is the proposed feeding mechanism given limited functional dentition. Echolocation clicks provide a way to detect nearby prey and barriers, distinct from the tusk's mechanical contact.[1]

A COMMON MIX-UP

Is the spiral structure a horn grown from the forehead?

No. It is a canine tooth extending from the upper jaw.[1]

TRY A LITTLE REASONING

Why does a feeding female without an erupted tusk challenge the idea that every fish is speared?

Reveal the explanation

Successful feeding does not require a visible spear; suction and prey capture can occur without one.[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 — Narwhal (cited revision)
  2. NCBI Taxonomy — Monodon monoceros

Last fact check:

One discovery leads to another

Beluga whaleA beluga can turn its head without turning its whole body.Delphinapterus leucas ↗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 ↗