What do a mouse and a rat look like? - briefly
A mouse measures about 2–4 inches in body length, has a slender build, a pointed snout, relatively large ears, and a long, hair‑covered tail roughly equal to its body. A rat is larger, 6–9 inches long, exhibits a robust body, blunt snout, smaller ears, and a thick, scaly tail shorter than its body.
What do a mouse and a rat look like? - in detail
Mice and rats share the basic rodent body plan—compact torso, short limbs, whiskered face—but differ markedly in size, proportions, and external details.
- Size: adult house mice (Mus musculus) typically weigh 10–25 g and measure 6–9 cm from nose to base of tail; adult Norway rats (Rattus norvegicus) weigh 200–500 g and reach 20–25 cm in body length, with tails adding another 15–25 cm.
- Tail: mouse tail is slender, roughly equal in length to the body, covered with fine hair and often slightly tapered; rat tail is thicker, longer than the body, hairless, and often exhibits a darker, scaly appearance.
- Ears: mouse ears are proportionally large, round, and hairless, extending close to the head’s top; rat ears are smaller relative to head size, oval, and may have a thin layer of fur on the outer edge.
- Snout and nose: mouse snout is short with a pointed tip; rat snout is longer, more robust, and the nose appears broader.
- Fur: mouse fur is soft, dense, and commonly gray, brown, or black; rat fur is coarser, less dense, and varies from brown to black, occasionally showing a reddish hue on the ventral side.
- Feet: mouse hind feet are small, with a noticeable pad and long, slender toes; rat hind feet are larger, with broader pads and shorter toes.
Skeletal structure reflects these differences: mouse skull is lighter with a higher brain-to-body ratio, while rat skull is heavier with stronger jaw muscles. The dental formula is identical (one pair of incisors per quadrant), yet rat incisors are larger and more robust, supporting a stronger gnawing capability.
Overall, the visual contrast lies in the mouse’s diminutive, delicate form and proportionally large ears and tail, versus the rat’s substantial, sturdier build, longer hairless tail, and broader facial features. These characteristics enable reliable identification in field observations and laboratory settings.