THE ANIMAL FILES

Saharan horned viper

Cerastes cerastes

The horns can be missing from a horned viper.

The Saharan horned viper offers a useful identification lesson: the scales above its eyes may form horns, but they can be reduced or absent. Sand-colored patterns, sidewinding and concealed ambush positions reveal a desert animal that cannot be understood from its name alone.[1]

Follow the evidence ↓
Saharan horned viper
Image: Holger Krisp · Commons · CC BY 3.0
Horns
Can be reduced or absent[1]
Movement
Often sidewinds on sand[1]
Food
Lizards, small rodents and birds[1]

A variable feature above the eyes

The characteristic horns arise above the eyes, but their expression varies among individuals. Background color also varies in pale tones associated with the substrate. A memorable feature can help an observer know what to examine, while its absence should not be used alone to rule out the species.[1]

Leaving a sideways trail

Sidewinding places successive body regions against the sand and leaves characteristic impressions. These tracks record where the body contacted the surface as it moved.[1]

A hidden hunting position

The species commonly ambushes prey while partly concealed in sand near rocks or vegetation. Its diet includes lizards, small rodents and birds. Concealment reduces exposure to both prey and potential predators.[1]

A COMMON MIX-UP

Can the missing horns alone exclude this viper?

No. Individuals can have reduced horns or no horns. Several features must be considered together.[1]

TRY A LITTLE REASONING

What extra information does a track give beyond a photograph of a resting snake?

Reveal the explanation

It records the pattern of body contact during movement. A trail can therefore reveal a process that a resting outline cannot.[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 — Cerastes cerastes (adapted and translated; exact revision)
  2. NCBI Taxonomy — Cerastes cerastes (identity and game lineage)

Last fact check:

One discovery leads to another

AdderA northern snake’s year includes a long winter pause.Vipera berus ↗Western diamondback rattlesnakeDiamond marks and a banded tail tell different parts of the pattern.Crotalus atrox ↗Black mambaThe black in its name is inside the mouth.Dendroaspis polylepis ↗