Where did rats and mice originate? - briefly
Rats and mice first evolved in Asia, with the brown rat (Rattus norvegicus) originating in China and the house mouse (Mus musculus) emerging in the Middle East–South Asian region. Their spread worldwide followed human trade and settlement patterns.
Where did rats and mice originate? - in detail
Rats and mice belong to the family Muridae, which emerged in the early Oligocene (≈30 million years ago). Fossil genera such as Paleomys and Megalomys show that primitive murids first appeared in Eurasia, with the earliest confirmed specimens recovered from Asia‑European deposits in Mongolia and the Czech Republic.
The two most familiar genera diverged later:
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Genus Rattus – Ancestors of modern rats originated in Southeast Asia. Molecular clocks place the split of Rattus from other murids around 12 million years ago. The species Rattus rattus (black rat) and Rattus norvegicus (brown rat) evolved in the Indian subcontinent and southern China, respectively, before expanding their range through maritime trade routes during the last two millennia.
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Genus Mus – The house mouse (Mus musculus) traces its roots to the Indian subcontinent and surrounding regions. Genetic studies indicate a divergence from related Mus species roughly 5 million years ago, with subsequent radiation across temperate Eurasia.
Archaeological evidence supports these timelines. Rat bones appear in Neolithic sites of the Levant and China (≈10 kyr BP), while mouse remains are found in early agricultural settlements of the Fertile Crescent (≈9 kyr BP). Both taxa spread rapidly with human agriculture and urbanization, exploiting stored grain and waste.
Key factors in global dispersal:
- Maritime commerce – Black rats hitchhiked on ships from Asia to Europe and Africa in the medieval period.
- Overland trade routes – House mice followed caravans along the Silk Road into Central Asia and Europe.
- Urban environments – Dense human habitats provided continuous food sources, allowing populations to establish and expand.
In summary, rats originated in Southeast Asian regions, while mice have their earliest evolutionary roots in the Indian subcontinent. Their worldwide presence results from a combination of ancient diversification within Muridae and recent human‑mediated movement.