Where did bats appear? - briefly
The earliest known bat fossils date to the early Eocene, roughly 52 million years ago, and were discovered in the Green River Formation of present‑day Wyoming, USA. Subsequent specimens from the same period appear in European deposits, indicating a rapid early diversification across the Northern Hemisphere.
Where did bats appear? - in detail
Bats originated in the early Eocene, approximately 52 million years ago, as indicated by the oldest known fossil « Icaronycteris index » from the Green River Formation in present‑day Wyoming, United States. This specimen demonstrates fully developed flight membranes and echolocation structures, confirming that modern chiropteran features were already present at that time.
Subsequent discoveries expand the geographic range of early bats:
- Europe: fossils of the genus « Palaeochiropteryx » recovered from the Messel Pit in Germany illustrate a contemporaneous European presence.
- Asia: specimens attributed to « Archaeonycteris » found in the Okanagan Highlands of Canada and in the early Eocene deposits of China suggest rapid dispersal across continents.
- Africa: limited Eocene material, such as teeth attributed to early vespertilionid lineages, indicate a later colonization of the continent.
The distribution pattern implies that early chiropterans rapidly exploited aerial niches worldwide, facilitated by the warm, humid climate of the early Eocene, which supported abundant insect prey and forested habitats. Molecular clock analyses corroborate the fossil record, estimating the divergence of the two major bat clades—Yinpterochiroptera and Yangochiroptera—around 63 million years ago, shortly after the Cretaceous–Paleogene extinction event.
In summary, the earliest bat fossils appear in North America, with contemporaneous evidence from Europe and Asia, demonstrating a near‑global emergence of the order during the early Eocene.