What do laboratory mice look like? - briefly
They are small rodents about 7–10 cm in body length, weighing 20–30 g, with a short, hairless tail roughly equal to the body length. Coat colors are usually white (albino), black, or gray, and they have rounded ears and a blunt snout.
What do laboratory mice look like? - in detail
Laboratory mice are small rodents, typically weighing 20–30 g as adults and measuring 7–10 cm in body length, with tails of comparable length. Their bodies are compact, with a rounded torso, short limbs, and a pointed snout. The skull is proportionally large, featuring a pronounced occipital plate and well‑developed auditory bullae.
Coat coloration varies by strain, but the most common phenotypes include:
- Albino – white fur, pink eyes, and pink nose skin; lack melanin.
- Black – uniformly dark fur, black eyes; melanin present throughout.
- Agouti – mixed brown and black hairs giving a speckled appearance; dark eyes.
- Hairless – minimal fur, exposed skin; used for dermatological studies.
Fur is fine, soft, and lies close to the skin. Hair length is uniform across most strains, except for specialized lines (e.g., long‑hair mutants) where guard hairs extend beyond the undercoat.
Ears are relatively large, thin‑skinned, and positioned laterally on the head, providing acute auditory sensitivity. Eyes are prominent, with a horizontal pupil shape; visual acuity is modest compared to other mammals. The tail is slender, covered with a thin layer of fur, and functions in thermoregulation.
Sexual dimorphism is subtle. Males generally exhibit slightly larger body mass and a more pronounced anogenital distance. Both sexes possess well‑developed incisors that continuously grow, requiring gnawing to prevent overgrowth.
Age influences appearance. Neonates have pink, hairless skin and closed eyes. Juveniles develop fur color patterns characteristic of their strain within two weeks. Adult mice display full coat density and mature dentition. Senescent individuals may show alopecia, weight loss, and reduced skin elasticity.
Physiological traits linked to appearance include a high metabolic rate, rapid heart rate, and a basal body temperature around 37 °C. The integumentary system is adapted for quick wound healing, a feature exploited in many experimental protocols.
Overall, laboratory mice present a standardized morphology that facilitates reproducible research, with variations deliberately selected to match specific scientific objectives.