Bats take flight
Onychonycteris has full wings and claws on every finger — flight arrives before echolocation.
- When
- Known to
- ± 500 thousand years
- Era
- Eocene, Cenozoic
Onychonycteris finneyi, from the Green River shales, is the most primitive bat known from a complete skeleton. Its wings are fully formed and it clearly flew, but it retains claws on all five fingers and — critically — lacks the enlarged cochlea that laryngeal echolocation requires. That settles a long-standing question in the right order: bats learned to fly first and to echolocate afterwards. Bats become the second-largest mammal order and the only one to achieve powered flight.