Who was the ancestor of the rat? - briefly
The rat’s forebear is an early murid rodent that appeared in the early Oligocene, represented by fossils of the genus Pseudocricetomys. These primitive muroids gave rise to the modern Rattus species.
Who was the ancestor of the rat? - in detail
The evolutionary lineage of modern rats traces back to early members of the family Muridae, which emerged during the Oligocene epoch, roughly 34–23 million years ago. The earliest recognized murid species, Pseudomys and Progonomys, exhibit dental and skeletal characteristics that bridge primitive rodent forms and later rats. Fossil evidence from Asia and Europe shows that Progonomys possessed the incisor morphology and skull structure that foreshadowed the genus Rattus.
Subsequent diversification produced the genus Rattus in the Miocene, about 12–15 million years ago. The direct predecessor of contemporary rats is Rattus species such as Rattus (Rattus exulans) and Rattus (Rattus norvegicus) ancestors, which evolved from earlier murids like Paracricetodon and Apodemus‑like forms. These ancestors display:
- Hypsodont molars with complex occlusal patterns.
- Enlarged auditory bullae, a trait linked to nocturnal activity.
- Adaptive limb morphology for rapid terrestrial locomotion.
Molecular phylogenetics corroborates the fossil record, indicating that the common ancestor of all extant rats diverged from other murids approximately 10–12 million years ago. This ancestor possessed the genetic markers shared by present‑day Rattus species, including specific mitochondrial DNA haplotypes and nuclear gene sequences related to metabolism and reproduction.
In summary, the rat’s ancestry originates in Oligocene murid rodents, progresses through Miocene genera such as Progonomys and Paracricetodon, and culminates in the emergence of the genus Rattus during the late Miocene, establishing the lineage that gave rise to today’s worldwide rat populations.