Characteristics of Commensal Rodents

Different rodent characteristics at a glance

Characteristics of Commensal Rodents

A quick at a glance chart of the differences between mice and rats

roof rats

Roof Rats

  • Characteristic: Sleek, graceful
  • Adult size: 5-9oz/150-250g
  • Length: (nose to tip of tail):6-8 in/16-20cm
  • Snout: Pointed
  • Ears: Large, nearly naked;can be pulled over eyes
  • Eyes: Large, prominent
  • Tail: Uniformly dark
  • Fur: Gray to black ; abdomen, gray, or black; smooth
  • Droppings: Spindle shaped, 1 cm/0.5 inch
  • Senses:
    • Sight: Poor,color blind
    • Smell, Taste, Touch, Hearing: Excellent
  • Food: Omnivourous, especially fruits, nuts,grains, and vegetable (15-30 grams/day) 0.5-1.0 oz/day
  • Water: 15-30 ml/day
  • Feeding Habits: Shy (new object reaction);steady eater
  • Climbing: Very agile, active climber
  • Nests: Walls, attics, vines, trees;sometimes burrows
  • Swimming: Can swim
  • Home Range Radius: 30-50 m/98-164 ft.
  • Age at mating (months): 2-3
  • Breeding season: Spring and Fall peaks
  • Gestation period (days): 22
  • Young per litter: 4-8
  • Litters per year: 4-6
  • Young weaned/female/year: 20
  • Length of life: 1 year
norway rats

Norway Rats

  • Characteristic: Large, robust
  • Adult size: 7-18oz/200-500g
  • Length: ((nose to tip of tail): 7-9.5in/18-25cm
  • Snout: Blunt
  • Ears: Small, covered with short hairs; do not reach eyes
  • Eyes: Small
  • Tail: Dark above, pale beneath
  • Fur: Brown with scattered black; abdomen -gray to yellow-white;shaggy
  • Droppings: Capsule shaped, 2cm/3/4-1 inch
  • Senses:
    • Sight: Poor,color blind
    • Smell, Taste, Touch, Hearing: Excellent
  • Food: Omnivorous(22-30grams/day) 0.8-1 oz.
  • Water: 15-30 ml/day
  • Feeding Habits: Shy (new object reaction);steady eater
  • Climbing: Readily climbs, limited agility
  • Nests: Usually burrows
  • Swimming: Excellent swimmer
  • Home Range Radius: 30-50 m/98-164 ft.
  • Age at mating (months): 2-3
  • Breeding season: Spring and Fall peaks
  • Gestation period (days): 22
  • Young per litter: 8-12
  • Litters per year: 4-7
  • Young weaned/female/year: 20
  • Length of life: 1 year
house mice

House Mouse

  • Characteristic: Small, Slender
  • Adult size: 0.4-1 oz/12-30 g
  • Length:(nose to tip of tail):2-3.5 in/6-9cm
  • Snout: Pointed
  • Ears:
  • Eyes: Small
  • Tail: Uniformly dark
  • Fur: Light brown, light gray; smooth
  • Droppings: Rod shaped, 3-6 mm/0.5 inch
  • Senses:
    • Sight: Poor,color blind
    • Smell, Taste, Touch, Hearing: Excellent
  • Food: Omnivourous, prefers cereal grains(3 grams/day) 0.1 oz. day
  • Water: 3-9 ml/day;can subsist without water
  • Feeding Habits: Inquisitive, nibbler
  • Climbing: Good climber
  • Nests: Within structures, stored food; burrows
  • Swimming: Can Swim
  • Home Range Radius: 3-10m/10-33 ft.
  • Age at mating (months): 2-3
  • Breeding season: Year long
  • Gestation period (days): 19
  • Young per litter: 4-7
  • Litters per year: 8
  • Young weaned/female/year: 30-35
  • Length of life: 1 year

* From Truman's Scientific Guide Sixth Edition

Note: Data are averages and not representative of extremes.

Sources: Compiled from J.E. Brooks and F.P. Rowe, Commensal Rodent Control(World Health Organization,WHO/VBC/79.726, Geneva,1979);W.E. Howard and R.E. Marsh, The Rat:Its Biology and Control(Univ.of California, Division of Agriculture Sciences, leaflet no 2,896,1976); H.D. Pratt and R. Z. Brown, Biological Factors in Domestic Rodent Control( U.S. Department of Health, Education and Welfare , Centers fo Disease Control, bulletin no 76-8144, 1976);R. E. Marsh and W.E. Howard, The House Mouse: Its Biology and Control(University of California, Division of Agricultural Sciences, leaflet no. 2,945, 1977);W.B Jackson, "Norway Rats and Allies," in Wild Mammals of North America, ed J.A. Chapman and G. A.Feldhamer(Baltimore: Johns Hopkins University Press, 1982)

Top Rodent Bait and Traps

Written by our resident pest control expert Ken Martin.