Brown Rat ( Rattus norvegicus)

-   Length up to 40cm with a tail shorter than the head and body
-     Weight 350-500g
-     Blunt nose, small ears and thicker body when compared to the Black Rat ( Rattus rattus)
-     7- 8 young per litter, 3-6 litters a year
-     Gestation period of about 3 weeks
-     10-12 weeks from birth to sexual maturity
-     Usually ground living and burrowing but sometimes climbs
-     The only species to occur in sewers in Hong Kong
-     Prefer food in cereals

Black Rat (Rattus rattus)

-   Length 15-25cm with a tail longer than the head and body
-     Weight 150-200g
-     Pointed nose. Large ears and a slender body when compared to the Brown Rat (Rattus norvegicus)
-     5-10 young per litter, 3-6 litters a year
-     Gestation period of about 3 weeks
-     12-16 weeks from birth to sexual maturity
-     Rare in Hong Kong
-     Appearance confined mainly to ports
-     Often climbs, agile, rarely burrowing and rarely outdoors in Hong Kong
-     Preferred food is most fruits
-     Consume around 15g of food and drink 15ml a day

House Mouse ( Mus domesticus)

-    Length 6-9cm with a tail around the same length
-       Weight 12-30g
-      Their relatively small feet and head and large eyes & ears distinguish them from a young brown rat (Rattus norvegicus)
-       4-16 young per litter, 7-8 litters a year
-       Gestation period of about 3 weeks
-       8-12 weeks from birth to sexual maturity
-       Usually ground living and burrowing but often climbs
-       Preferred food is cereals
-       Consume around 3g of food a day and can survive without any additional water