What is a large house mouse called? - briefly
A large specimen of the common house mouse is generally referred to as a rat, most commonly the Norway rat (Rattus norvegicus). It belongs to a different genus within the same order of rodents.
What is a large house mouse called? - in detail
The common house mouse (Mus musculus) occasionally reaches a size noticeably greater than the average adult, typically exceeding 30 g and a body length of 10 cm. In scientific literature such specimens are referred to as “large Mus musculus” or “giant house mouse.” The term “field mouse” is sometimes applied to larger individuals of the same species when they inhabit outdoor environments, but it does not denote a separate taxon.
Key characteristics of an unusually large domestic mouse:
- Body mass: 30–45 g (average house mouse 15–25 g).
- Head‑body length: 9–12 cm, tail length comparable to body.
- Fur coloration: standard brown‑gray dorsal coat, may appear more robust.
- Skeletal growth: elongated femur and humerus, indicating prolonged development.
Classification remains Mus musculus; the size variation reflects genetic factors, abundant nutrition, and reduced predation pressure. Breeding programs occasionally select for larger size, producing “laboratory giant mouse” strains used in biomedical research.
In field reports, observers may label such individuals “large house mouse” or “giant mouse” for brevity, but taxonomically they belong to the same species as their smaller counterparts.