To which species do mice and rats belong? - briefly
Mice and rats are rodents in the order Rodentia and family Muridae; mice are assigned to the genus Mus, whereas rats belong to the genus Rattus. Both genera are mammals within the class Mammalia.
To which species do mice and rats belong? - in detail
Mice and rats are members of the class Mammalia, phylum Chordata, and kingdom Animalia. Within mammals they belong to the order Rodentia, which comprises the largest group of living mammals. Both genera are placed in the family Muridae, the “true mice and rats,” and more specifically in the subfamily Murinae.
The genus Mus contains the common house mouse (Mus musculus) and several related species. The genus Rattus includes the brown rat (Rattus norvegicus) and the black rat (Rattus rattus) among other taxa. Although both genera share the same family, they differ at the genus level, reflecting distinct evolutionary lineages.
Key taxonomic ranks for these rodents are:
- Kingdom: Animalia
- Phylum: Chordata
- Class: Mammalia
- Order: Rodentia
- Family: Muridae
- Subfamily: Murinae
- Genus: Mus (mice) or Rattus (rats)
Morphologically, members of Mus are typically smaller, with a head‑body length of 6–10 cm, whereas Rattus species range from 15–25 cm. Dental formulae are identical (1/1 incisors, 0/0 canines, 0/0 premolars, 3/3 molars), a defining feature of Muridae, but cranial and skeletal structures exhibit genus‑specific variations used in taxonomic identification.
Genetic studies confirm that mice and rats share a common ancestor within Murinae, diverging approximately 12–15 million years ago. This divergence is evident in mitochondrial DNA sequences and in the organization of the major histocompatibility complex, which underpins differences in immune response and disease susceptibility.
In summary, both groups are classified as murine rodents, occupying the same family but distinct genera, with differences in size, morphology, and genetic lineage that justify their separate taxonomic status.