Rats vs. mice

Rats and mice are some of the most prevalent and important pests in homes and businesses due to their ability to adapt to the human environment.

These are the Norway rat (also known as the brown rat), the Roof rat (sometimes called the ship rat or black rat), and the House mouse. Mice and rats can vary in appearance and are found worldwide.

All rodents have the common identifying feature of a pair of incisor teeth in the upper jaw. They tend to have short legs and a long tail, but a closer look at their body characteristics and habits shows that there are easily distinguishable features that you can use to identify which pest is invading your property.

Mice

The easiest distinguishing feature is the small size of the house mouse at less than 4 inches long. However, a mouse can be confused with a young rat.

• Mice have long, hairy tails.
• They are usually light grey or brown in colour with a lighter shade on their bellies.

Rats

Rats have a similar appearance to mice but have distinguishable differences.

• Rats typically have a body length of 6-9.5 inches.
• Norway rats have coarse brown or gray fur with white on their abdomen.
• Roof rats can be entirely black, dark gray or brown with white on the abdomen.
• Rat tails are scaly with no hair.

Both rats and mice are omnivorous but the Norway rat and house mouse prefer cereals, while roof rats prefer fruit and foods with high moisture content.

Norway rats:

• Prefer cereals
• Cut grain when eating, giving the appearance that it has been chopped
• Tend to seek food in the same places, making baiting easier
• Drink about 15 - 30 ml (1/2 - 1 oz) of water a day

Roof rats:

• Prefer naturally-occurring seeds, nuts, fruits, and berries but will eat a variety of dry human and pet foods
• Cut grain when eating, giving the appearance that it has been chopped
• Tend not to eat at the same location on consecutive nights, which makes them more difficult to control
• Baiting them requires many small points using moist food, which only remains edible for a few days before needing replacement
• Drink about 45 ml (1.5 oz) of water a day

Mice:

• Prefer cereals
• Eats grains by removing the outer husk to eat the white endosperm inside
• Tend to seek food in the same places
• Don’t need to drink water but will drink about 1.5 ml (.05 oz) from food if available

Norway rats usually live on the ground or in burrows. They are usually spotted throughout buildings, in sewer systems and outdoors. Their burrowing can cause extensive damage to sewers. The Norway rat tends to walk on the pads of the feet and the surfaces on which it travels show continuous smudges from the oily fur.

Roof rats are mainly restricted to buildings around ports and on ships in temperate countries (hence the name ‘ship rat’). They are agile and good climbers, nesting high up under roofs and low inside buildings. In warmer countries, where they originate, Roof rats will nest in trees, especially in woodland and orchards. Roof rats tend to walk on their toes and leave behind sebum (grease/rub marks) on the surfaces they travel along.

Mice usually live on the ground and nest in burrows, but are agile and can climb. In heavy infestations, grease from the body combined with dirt and urine can build into small pillars. These can remain for a long time, so they may not indicate a current infestation.

Norway rat droppings

Norway rat droppings are wide and are dark brown in colour. They are typically found in a tapered, spindle shape – resembling a large sunflower seed.

Roof rat droppings

Roof rat droppings have pointed rather than blunt ends but look similar to Norway rat droppings in colour occasionally with more of a curved shape.

Mice droppings

Mouse droppings are smaller than other rodent droppings, about 1/4 inch long (6 mm). Their droppings are often found scattered randomly during an infestation. Mouse droppings are cylindrical in shape and black in colour, often found near nesting areas.

Mice reach sexual maturity earlier and produce larger litters at a more frequent rate than rats. The newborns of all three rodents are blind, hairless and completely dependent on the mother for feeding and protection.

House mouse

• Litter size: 5-6
• Litters per year: 6-10
• Time to maturity: 6-12 weeks

Norway rat

• Litter size: 4-7, up to 20 for a mature rat
• Litters per year: 3-6
• Time to maturity: 8-20 weeks

Roof rat

• Litter size: 6-8
• Litters per year: 4-6
• Time to maturity: 12-20 weeks

If you have spotted mice or rats in or around your property, don’t hesitate to contact us today at 1-877-690-2115 to speak to one of our pest control experts.