The House Mouse (Mus musculus) is a common rodent pest inside people’s homes. They are usually around three inches long and weigh less than an ounce. They’re quite a bit smaller than rats. They can have up to a dozen litters per year, and up to a dozen baby mice per litter. That’s gross! Average litter size is closer to six. They rarely live longer than a year in the wild.
Mice have excellent hearing and sense of smell, but poor eyesight. They often travel via urine or pheromone pathways. They have excellent speed and balance, and can easily climb most surfaces. Because they are so small, mice can fit through very tiny holes and gaps in building architecture. I mean, like 3/8 inch gaps, and holes the size of a dime! If they can get their tiny skulls through, the rest of the body slides through like putty.