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Description and Physical Characteristics of Mice


Katherine E. Quesenberry

, DVM, MPH, DABVP (Avian);

Thomas M. Donnelly

, BVSc, DVP, DACLAM, DABVP(ECM), The Kenneth S Warren Institute

Last full review/revision Jun 2020 | Content last modified Jun 2020
Topic Resources

Adult mice typically weigh about 1 ounce (28 grams) and are approximately 2.5 to 3.5 inches (6 to 8 cm) long, not including the tail (see Table: Mice at a Glance). Male mice are typically larger than females. Pet mice are available in many colors and coat patterns due to specialized breeding. Coats can be smooth, curly, longhaired, or a combination. The most common color variations are brown, black, tan, gray, and albino, with lighter and darker shades of these as well. The usual life span of mice is 1.5 to 2.5 years.


Mice at a Glance

Life span

1.5 to 2.5 years


20 to 40 g

Length (including tail)

6 to 7 in (15 to 18 cm)

Normal body temperature

98°F to 101°F (36°C to 38°C)

Heart rate

450 to 600 beats per minute

Estrous cycle

4 to 5 days

Duration of pregnancy

19 to 21 days

Litter size

10 to 12 young

Weaning age

21 to 28 days

For More Information

Also see professional content regarding mice as pets.

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