Dolphins and porpoises radiate
Toothed whales diversify into the fast, social, highly acoustic animals of the modern ocean.
- When
- —
- Duration
- 15 million years
- Known to
- ± 2 million years
- Era
- Miocene, Cenozoic
The delphinoid radiation through the Miocene produces oceanic dolphins, porpoises and belugas, along with river dolphins that repeatedly colonise freshwater systems — the Amazon, the Ganges, the Yangtze — as those rivers form. Echolocation reaches its modern refinement, and with it the large brains and complex social structure that make dolphins one of the very few groups outside primates where individual recognition, cooperative hunting and signature calls are well documented.