Where did mice originate in nature? - briefly
Mice trace their evolutionary roots to early murid rodents that first appeared in Asia roughly 10–12 million years ago, subsequently dispersing across continents. Their diversification resulted in the widespread species observed today.
Where did mice originate in nature? - in detail
Mice belong to the family Muridae, a lineage that emerged during the early Paleogene, roughly 55–60 million years ago. Fossil records indicate that primitive murids appeared in Eurasia shortly after the extinction of non‑avian dinosaurs, exploiting newly available ecological niches.
The earliest confirmed murid specimens are found in the early Eocene deposits of Europe, such as the Messel Pit in Germany. These fossils display dental and skeletal characteristics that link them to later genera, including Mus and Apodemus. Parallel findings in North America, notably in the Wasatch Formation (early Eocene), suggest a rapid dispersal across the Northern Hemisphere.
Key factors that drove the spread of early mice include:
- Adaptable diet: omnivorous feeding habits allowed exploitation of seeds, insects, and carrion.
- High reproductive rate: short gestation and large litter sizes facilitated population expansion.
- Burrowing and climbing ability: morphological traits enabled occupation of diverse microhabitats, from forest floor litter to arboreal niches.
During the Oligocene and Miocene, murids diversified into numerous subfamilies, with Mus species becoming dominant in temperate and subtropical regions. The genus Mus likely originated in South‑East Asia, as indicated by the concentration of basal fossils in the Tibetan Plateau and surrounding areas. From there, species migrated westward into Europe and eastward into the Indian subcontinent, eventually reaching Africa via land bridges.
Later glacial cycles of the Pleistocene prompted further range shifts. Populations retreated to refugia in southern Europe, the Near East, and East Asia, then recolonized northern territories during interglacial periods. This dynamic history accounts for the broad distribution of modern house mice (Mus musculus) and related species across all continents except Antarctica.
In summary, the evolutionary origin of mice traces back to early Paleogene murids in Eurasia, with subsequent diversification driven by dietary flexibility, reproductive strategy, and habitat versatility, leading to a worldwide presence through successive geological epochs.