Rat vs. Mouse

Rat (brown rat) and mouse (house mouse) are types of rodents that belong to the family Muridae. Pakistan is home country of mouse, while rat originates from China. These two types of murids can be found all over the world today. They inhabit forests, savannas, grasslands, rural and urban areas and live in close proximity of humans. Both animals are classified as pest because they inflict damage on the crops and spread various diseases. Even though they are members of the same family, rat and mouse can be easily distinguished via following features:

Size of the Body and Tail

Rat is larger, heavier and longer than mouse. It can reach 12.3 to 23 ounces of weight and 9 to 11 inches in length. Rat has long, scaly tail that is slightly shorter than the rest of the body. It can reach 7 to 9 inches in length. Mouse is small rodent that can reach weight of 1 to 1.8 ounces and length of 3 to 4 inches. It has long, skinny and slightly hairy tail that is usually same-sized as the body (3 to 4 inches). Rat has shorter, but thicker tail compared with a mouse.

Shape of the Head

Rat has large, broad head with blunt snout, while mouse has small triangular head with pointed muzzle. Rat has smaller ears and eyes (relative to the size of head) compared with mouse.

Coat

Mouse can be white, gray or brown colored, while rat can be white, gray, brown or black. Rat has coarser and greasier fur than mouse.

Genetics

Rat has 22 chromosomes, while mouse has 20 chromosomes.

Burrows

Mouse live in small, shallow burrows. It often uses soft material (such as paper) to build nest. Rat, on the other hand, lives in long and deep burrows that are usually located under buildings, fences, vegetation and plant debris.

Encounter in the Wild

Rat has natural instinct to hunt, kill and eat mouse. This behavior is known as muricide. That's why mouse shows signs of stress and has breeding difficulties when it detects rat's odor.

Gestation and Early Development

Pregnancy in rats lasts 21 to 24 days. Babies open their eyes after 6 days and develop fur at the age of 15 days. They depend on the mother's milk until the age of 3 weeks. Gestation in mice lasts 19 to 20 days. Babies are able to see 3 days after birth and they are fully furred at the age of 10 days. Lactation period in mice lasts only 2 weeks.

Lifespan