Characteristics Of Commensal Rodents


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

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

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: Large, some hair

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)