Where did mice originate on Earth? - briefly
The oldest murine fossils are found in Eurasian strata from the early «Miocene», roughly 20 million years ago. From that region, the lineage expanded across continents, establishing the worldwide presence of mice.
Where did mice originate on Earth? - in detail
Mice belong to the genus Mus within the family Muridae, a lineage that diversified during the Miocene epoch. Fossil remains attributed to early Mus species have been recovered from the Late Miocene deposits of the Tibetan Plateau and the Gansu region of China, indicating an Asian origin for the group. Additional early‑Pliocene specimens from Mongolia and Kazakhstan extend the known range of ancestral forms across the Eurasian steppe.
Molecular phylogenetic analyses of mitochondrial and nuclear DNA place the most recent common ancestor of extant Mus lineages at approximately 5–7 million years ago. These studies consistently identify a primary radiation in South‑East Asia, with subsequent lineages branching toward the Indian subcontinent, the Middle East, and the Mediterranean basin. Divergence estimates suggest that the Mus musculus complex originated in the Indian subcontinent before expanding westward into Europe and northward into temperate Asia.
Biogeographic reconstructions indicate three major dispersal events:
- Expansion from the Indian subcontinent into the Near East and Europe during the early Pleistocene.
- Colonization of the African continent via the Levantine corridor in the mid‑Pleistocene.
- Introduction to the Americas through human‑mediated transport beginning in the 16th century, followed by rapid establishment in diverse habitats.
Ecological adaptability, high reproductive rates, and omnivorous diet facilitated the successful spread of mice across varied environments. Contemporary distributions show the highest species richness in tropical and subtropical Asia, supporting the hypothesis of an Asian cradle for the genus.
Key points summarizing the origin and spread:
- Earliest Mus fossils: Late Miocene, Tibetan Plateau and northern China.
- Molecular clock: common ancestor 5–7 Ma, primary radiation in South‑East Asia.
- Major dispersal routes: Indian subcontinent → Europe; Levant → Africa; human‑aided introduction → Americas.
- Present diversity peaks in Asian tropical and subtropical regions.