Mice vs Rats: everything you need to know

Jordan SteinbergMay 8, 2017

What do mice and rats look like?

Mice and rats are both short-haired rodents. Mice are completely covered in fur, while rats' ears and tails are hairless. Both of their stomachs are light in color, while their bodies can be black, grey, or brown. 

Mice often grow to six or eight inches in length. Their fur can range in color from black to grey to brown across their heads, ears, bodies and tails. Their stomachs will always be of a lighter shade. By adulthood, the average mouse will weigh between 10 and 30 grams.

Rats, on the other hand, only have fur on their bodies—their tails and ears are hairless. As with mice, rats’ coloration widely ranges black to grey, with their bellies always being a lighter white. At the time of maturation, a male rat will have an average weight of four-fifths of a pound, and a length of nine to eleven inches.

What do mice and rats eat?

Both mice and rats are omnivorous, meaning that they can eat both meat and vegetation. In practice, this dietary freedom results in frequent consumption of fruits and grains. In the case of rats, they may also consume small bugs and animals. As all these are often found in gardens and farms, mice and rats are typically drawn to these areas.

How long do mice and rats live?

Outside of domestication, it is not common for mice to live longer than 18 months. When kept as pets, however, a lifespan of roughly two years should be expected. In a laboratory setting, mice have been known to live as long as three to five years.

In the wild, 95% of black rats do not survive their first year. If they do, however, female rats generally hit menopause at 18 months, and can expect to live no longer than 2 years. In a domestic setting, however, rats can typically enjoy a two to three year lifespan.

How often do mice and rats breed?

Mice become sexually active six weeks after birth. The gestation period for pregnant mice is three weeks. Each litter can range between three and fifteen young mice. On average, a female will give birth between five and ten times annually. Rats have a similar breeding cycle, with sexual maturity arriving at five weeks, a gestation period of 21 days, a range of seven to fourteen rats in each litter, and an average of five pregnancies per years.


Where do mice and rats live?

Being small and omnivorous, mice can live anywhere. When in the wild, mice will typically burrow underground in order to protect against overhead predators. This can be done either in forests or grasslands. In the case of rats, they may also settle in elevated locations, such as in trees or rafters. In manmade structures, mice and rats will find anywhere that’s protected, but within close proximity to a food or water source. In a home, this can include walls, cabinets, boxes and crawl spaces, and anywhere near the kitchen.

What are the signs of mice and rats?

There are certain telltale signs of mouse and rat infestation. The following are great examples of this:

  • Feces. Mouse droppings are black, pointed on both ends, and rod-shaped. Rat droppings are brown, bulging in the center, and rounded on the ends.
  • Scratching noises from within the walls.
  • Trails of footprints in dusty areas
  • Grease marks along tight areas where the mice are frequently active.
  • The presence of a nest
  • A strong urine smell where the mice are most active
  • Bite marks on food packaging

How to keep mice and rats away

By the time the signs of a mouse or rat infestation become visible, chances are that it’s already become serious. As such, it is best to prevent the possibility of an infestation before it begins. The methods of doing so are as follows:

  • Ensuring that water sources are not leaking
  • Checking that cabinets and refrigerators are not easily opened
  • Sealing holes and cracks in around the home to prevent entrance into the walls. Due to their size, rats are easier to exclude from the home.
  • Keeping garbage containers tightly sealed

How to get rid of mice and rats

Depending on the severity of the infestation in question, there are differing methods of resolution. In minor cases, do-it-yourself methods are the cheaper and more logical option. Examples of these methods include:

  • Natural sprays to ward off rodents
  • Bait & poison traps, though this could put young family members at risk
  • Snap traps, which kill instantly
  • Cage traps, which leave the mouse or rat alive
  • Glue traps, though these are considered highly inhumane.

Generally speaking, professional exterminators will employ these same traps and tactics. In the most critical of situations, fumigation may be warranted. Should their professional perspective be needed, our top 10 pest control specialists would be more than happy to assist.