Researchers have said that a fossilized whale skull found outside Charleston, South Carolina shows all the tell-tales signs that are related to echolocation in today's toothed whales, dolphins, and porpoises.
The skull is about 28 million years old, and belonged to what's now the oldest known creature which used echolocation to hunt, the Verge reported.
The whale, classified as Cotylocara macei, existed during in the same era when toothed whales and non-toothed whales branched off on the evolutionary tree.
That split occurred about 32 and 34 million years back, which means that echolocation evolved as far back as that time.
Lead study author Jonathan Geisler, a professor of anatomy at the New York Institute of Technology College of Osteopathic Medicine, said that most important conclusion of their study involves the evolution of echolocation and the complex anatomy that underlies this behavior.
Researchers say that the whale was slightly larger than a modern bottlenose dolphin and, crucially, has the asymmetrical skull structure and nasal passages that would allow for the vocalizations used in echolocative function.
The study has been published in the journal Nature.