THE ANIMAL FILES

Brown rat

Rattus norvegicus

A burrow is shelter, storage and a route away from disturbance.

Brown rats combine opportunistic feeding with substantial excavation. Burrows can contain several tunnels and entrances, while nearby resources influence foraging. Their sensitive hearing and smell provide information in settings where a human view of the surface reveals only a small part of the structure.[1]

Follow the evidence ↓
Brown rat
Image: Charles J. Sharp · Commons · CC BY-SA 4.0
Food
Both plant and animal resources[1]
Burrow functions
Shelter, nesting and food storage[1]
Tail proportion
Usually shorter than head and body combined[1]

A body supported by hearing and smell

Brown rats usually have brown or dark-grey upper fur with paler underparts. They have acute hearing, including sensitivity to ultrasound, and a developed sense of smell. Those sensory abilities help describe an animal that investigates complex spaces without relying on human-like visual resolution.[1]

Food use changes between populations

Cereals can be important, but the diet also includes animal food. Some populations catch fish or take aquatic molluscs. These are local feeding observations, not a requirement that every brown rat hunts the same prey wherever it lives.[1]

The entrance is the start of a structure

Burrows often begin beside a supporting object and develop into multiple tunnels with an additional entrance. They offer nest sites, food storage and places to retreat. The surrounding substrate matters because a stable roof near the surface helps maintain access to the underground space.[1]

A COMMON MIX-UP

Does an omnivorous species eat the same food everywhere?

No. Availability and population-specific behaviour change which resources are used. A fish-catching population demonstrates one possible strategy rather than the universal menu of the species.[1]

TRY A LITTLE REASONING

Why might a rat start a burrow beside a solid object?

Reveal the explanation

The object can support a stable roof near the surface. Excavation depends on material structure as well as the animal’s ability to dig, especially where an entrance must remain open.[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 — Brown rat (fixed revision; adapted and translated)
  2. NCBI Taxonomy — Rattus norvegicus (identity and classification)

Last fact check:

One discovery leads to another

House mouseA mouse can read a nearby surface with its whiskers.Mus musculus ↗Mongolian gerbilA grassland home with more than one exit.Meriones unguiculatus ↗Golden hamsterThose swollen cheeks are transport bags, not a giant swallowed meal.Mesocricetus auratus ↗