U.S. biologists have determined that, as bats developed sonar to chase flying insects, whales and dolphins developed sonar to chase squid at night. And because squid migrate to deeper, darker waters during the day, toothed whales eventually perfected an exquisite echolocation system that allows them to follow the squid down to that “refrigerator in the deep, where food is available day or night, 24/7,” said evolutionary biologist Professor David Lindberg of the University of California-Berkeley and coauthor of a new paper on the evolution of echolocation in toothed whales.
“When the early toothed whales began to cross the open ocean, they found this incredibly rich source of food surfacing around them every night, bumping into them,” said Lindberg, a curator at University of California-Berkeley’s Museum of Palaeontology. “This set the stage for the evolution of the more sophisticated biosonar system that their descendants use today to hunt squids at depth.”
Lindberg and graduate student Nick Pyenson reported their research in the July 23 online edition of the journal Lethaia in advance of its print publication.
Source: Science Daily
3 responses so far ↓
laelaps // September 28, 2007 at 8:26 pm |
I’ve always found the association of hearing in cetaceans (including echolocation) with the lower jaw. I’m sure you’re already familiar with the fact that the bones of the mammalian inner ear were exapted from bones in the jaws of their ancient ancestors, and it is interesting that dolphins pick up returning waves of sound from echolocation with their lower jaw. I haven’t studied this in depth (yet), but I would presume the lower jaw would route the sound right into the hearing apparatus, making the process more efficient underwater.
edtajchman // September 28, 2007 at 10:20 pm |
Isn’t there human technology eye adaptars that run on some of the same principals?
archaeozoo // September 29, 2007 at 11:29 am |
Laelaps, yes I have come across the evolution of the mammalian inner ear before, although like you I haven’t studied it in depth. It is something I find intriguing, however. Presumably, in much the same way as deaf musicians say they can ‘feel’ the music by detecting the vibrations, the bones of the lower jaw could be used to detect vibrations through the water.
Whether there are human technologies that specifically take advantage of that as you suggest edtajchman, I honestly cannot say for sure off the top of my head, although it certainly seems plausible.
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