Rodents as Pests
There are three rodent species which are responsible for most pest problems in the human environment worldwide: house mouse, brown rat and black rat.
Originally native to restricted geographical areas, they have adapted well to the human environment and been unintentionally introduced around the world by human travel and trade over thousands of years. They have different physical characteristics, feeding habits and behaviours which are used to identify them and their presence.
House mouse
(Mus musculus)
The house mouse is 3-10 cm long and has a tail the same length as the body. It has a smaller head and feet relative to the body than a young rat. It usually lives on the ground and in burrows. It prefers cereals for food and can survive without water, as long as their food source has a high moisture content.
Brown Rat
(Rattus norvegicus)
The brown rat is larger than the black rat and has a blunt nose. It also has a thicker body, small hairy ears and a shorter tail which is paler underneath. It prefers to eat cereals and needs more water to drink. It usually lives on the ground and in burrows. It is easy to control by laying bait, but needs specialist services for removal of infestations in sewers.
Black Rat
(Rattus rattus)
The black rat has a smaller, slender body. It has a pointed nose and large hairless ears, and its tail is longer than its body. It has arboreal origins so is agile and likes to climb for nesting. In temperate countries it is mainly confined to ports and ships. When found in buildings it usually nests high in the roof. It prefers fruit and moist bait, varying its routes for foraging, making it more difficult to bait.
Squirrels
Squirrels generally live in wooded areas and trees but are common pests in urban, suburban and rural areas in North America. They frequently invade attics and garages to take shelter and store food. In buildings they can gnaw on cables, stored goods in the exterior and interior walls. In gardens they can strip bark from trees and ornamental plants and damage flower beds.
Chipmunks
Chipmunks are burrowing rodents found in North America that forage mainly on the ground. They have an omnivorous diet, but feed primarily on seeds, nuts, fruit and buds. They can damage gardens, fruit and vegetables and burrow under buildings, damaging porches, patios etc.