House Mouse

Scientific Name: Mus musculus

Also Known As: Eurasian House Mouse

Range: All of Florida

Diet: Seeds, grains, plants

Life Expectancy: 9 - 12 Months

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Appearance and Identification
Habits and Behavior

Habitat and Range
Diet

Signs and Preventing

Round-tailed Muskrat (Florida Water Rat) in Central Florida

The house mouse (Mus musculus) is a small, prolific rodent that thrives in and around homes and buildings.

House mice pose significant economic and health risks if populations are not well-controlled. This guide covers house mouse identification, biology, behavior, health hazards, and prevention methods relevant to central Florida.

Appearance and Identification

House mice have characteristic features that distinguish them from other small rodents

Adult House Mice

Size: Adults reach 3-4 inches (7.5-10 cm) in body length, plus a 3-4 inch (7.5-10 cm) tail. They weigh about 1/2 to 1 ounce (14-28 grams).
Fur: Fur ranges from gray to brown with a characteristic agouti pattern of lighter belly and banded, darker guard hairs on the back.
Head: Pointed nose, prominent ears nearly as long as their head, and black beady eyes.
Tail: Long, naked tail with distinct scaly annuli. The tail aids balance.

Juvenile House Mice

Size: Newborns are about 1 inch (2.5 cm) long, weighing less than 1 gram. They reach 3-4 inches (8-10 cm) including the tail by 3-4 weeks old.
Fur: Sparse, soft gray or brown fur covers the body. Juveniles lack the agouti pattern of adults.
Features: Proportionally large head, feet, and ears compared to the body size. Pointed nose and small, bead-like black eyes.

Mature house mice are smaller with larger ears and eyes compared to rats. Their feet lack the rat’s long toes adapted for climbing and burrowing. House mice vocalizations are higher-pitched squeaks compared to the rumbling noises rats make.

Maturation Rate

Newborn pups are hairless, blind and dependent on the mother. They develop fur at 1 week and open their eyes at 2 weeks old. Weaning occurs by 3-4 weeks old as they transition to solid food. House mice reach reproductive maturity and near-adult size by 6 weeks old. They are independent at 4-5 weeks old.

Habits and Behavior

House mice are nocturnal but may venture out during the day if hungry. They have poor eyesight but keen senses of smell, taste, hearing, and touch. House mice are wary, nibbling small samples of new foods before eating more.

House mice are agile climbers and can walk up vertical surfaces but prefer horizontal movement. They can jump up to 12 inches (30 cm) high and survive falls from great heights uninjured. House mice can squeeze through very small spaces and openings just 1/4 inch (6 mm) wide.

They tend to forage within a 30 foot (10 m) radius of their nesting area. House mice are curious but avoid novel spaces and objects at first. Given time, they gradually habituate and explore new additions in their territory. House mice constantly explore and map out their surroundings.

Reproduction and Lifespan

House mice are fast maturing and prolific breeders. Females can start breeding as early as 6 weeks old and bear 5-10 litters per year. Litter sizes range from 4-12 young with a 21 day gestation period.

The average lifespan is just 9-12 months but house mice numbers rebound quickly after declines due to their high reproductive capacity. Females can conceive again within days after giving birth.