Norway Rat Scat and Tracks: How to Identify Them (Rattus norvegicus)

Rodent droppings are small and dark; shape and size are the first cut (rice-grain with pointed ends for mice, blunt and larger for rats, oval pellets for squirrels and voles). Tracks show four toes on the front foot and five on the hind, and most rodents bound, so the larger hind prints land ahead of the front prints. Gnaw marks with paired incisor grooves are often the clearest sign. The measurements below for Norway Rat are quoted from the wildlife agencies linked at the bottom of the page.

• Size: Up to 0.75 inches long, about 0.25 inches in diameter
• Shape: Blunt and rounded at both ends
• Contents/color: Fresh droppings are relatively soft in texture
• Where: A single mouse produces about 40-50 droppings per day, often clustered in small piles

• Gait: Tracks and tail-drag marks often appear on dusty surfaces or in mud

• Gnaw marks: Norway Rat gnaw marks are about 1/16 inch wide
• Burrow entrance: An active burrow entrance is 2-3 inches wide, clean around the opening, with mouse hair visible
• Grease/oil smudge marks: Grease and dirt from a rat's/mouse's body rub off onto beams, rafters, pipes, and walls, leaving marks

House Mouse droppings are slender and tapered at both ends, about 0.25 inches long; Norway Rat droppings are larger and blunt-rounded at both ends (0.5-0.75 inches) The House Mouse page has its own sign list.

The Norway Rat is somewhat larger than the Roof Rat

Human contact with the urine, droppings, and saliva of rats (including Norway Rats) can spread hantavirus If you need to clean it up, wear gloves and a mask, wet it down first, and bag it; see the CDC guidance linked in the sources.

Put something of known size next to it (a coin, a pen, a boot) and shoot straight down in soft light; low side light brings out the shape of tracks in mud or snow. For scat, photograph the whole deposit and one close-up showing contents. Note where it was: on a log, in the open, on a trail, near water. The app suggests the likely animal; confirm with the size and shape notes above.