A new fossil species supports an early origin for toothed whale echolocation

@article{Geisler2014ANF,
  title={A new fossil species supports an early origin for toothed whale echolocation},
  author={Jonathan H Geisler and Matthew W Colbert and James L. Carew},
  journal={Nature},
  year={2014},
  volume={508},
  pages={383-386}
}
Odontocetes (toothed whales, dolphins and porpoises) hunt and navigate through dark and turbid aquatic environments using echolocation; a key adaptation that relies on the same principles as sonar. Among echolocating vertebrates, odontocetes are unique in producing high-frequency vocalizations at the phonic lips, a constriction in the nasal passages just beneath the blowhole, and then using air sinuses and the melon to modulate their transmission. All extant odontocetes seem to echolocate… 

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