Filter feeding arrives
Baleen appears in the late Oligocene, and with it the ability to eat the smallest animals in the sea at the largest scale.
- When
- —
- Duration
- 3 million years
- Known to
- ± 1 million years
- Era
- Oligocene, Cenozoic
Archaic mysticetes such as Toipahautea from New Zealand show the transition toward toothless filter feeding, with reduced dentition and skull features associated with baleen. Baleen is keratin, the same material as hair and fingernails, hung in fringed plates from the upper jaw; it does not fossilise well, so its origin is inferred mostly from bone. Once in place it removes the upper limit on body size, because filtering scales with mouth volume — the largest animal that has ever lived is a direct consequence.