Friday Squid Blogging: Squid Controlled Evolution of Sonar in Whales and Dolphins
Behind the sailor’s lore of fearsome battles between sperm whale and giant squid lies a deep question of evolution: How did these leviathans develop the underwater sonar needed to chase and catch squid in the inky depths?
Now, two evolutionary biologists at the University of California, Berkeley, claim that, just as bats developed sonar to chase flying insects through the darkness, dolphins and other toothed whales also developed sonar to chase schools of squid swimming at night at the surface.
Because squid migrate to deeper, darker waters during the day, however, 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 David Lindberg, UC Berkeley professor of integrative biology and coauthor of a new paper on the evolution of echolocation in toothed whales published online July 23 in advance of its publication in the European journal Lethaia.
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Dom De Vitto • September 14, 2007 5:49 PM
Isn’t this obvious? Mother nature is pretty careful to only develop ‘features’ that are worth having, and features with little ‘return on the investment’ tend to be removed quickly.
So in a food scarce environment the ability to feed continuously, rather than just during the daylight hours, is a major advantage over your peers. Such a feature would mean you grow significantly larger, can survive longer food shortages, and ultimately successfully reproduce more often. The last point pretty much directly results in one species replacing others without that feature, that have the same food source.