Whales Evolved in the Blink of an Eye, Only 5 Million Years

Posted on June 10, 2010  Comments (0)

Whales Evolved in the Blink of an Eye

Whales’ sizes stretch the imagination from the 100-foot (30-meter) long blue whale – the largest animal to have ever existed – to a small species about the size of a dog.

Around 35 million years ago, when modern whales began to appear in the ocean, whale evolution ignited. Whales began as basically similar body types and evolved into everything from porpoises to blue whales over the next 5 million years, said study lead author Graham Slater of UCLA. “Five million years is like the blink of an eye,” Slater told LiveScience.

The finding supports what’s known as the explosive radiation hypothesis. The idea is that a few key traits allowed the earliest ancestors of modern cetaceans – marine mammals, including whales, dolphins and porpoises – to explore new ways of living. Once these ancestors branched out into a new body form, they stayed the course.

The key traits credited with the explosive evolution include sonar, large brains, baleen (the stringy looking stuff across some whales’ mouths that filters small animals from sea water), and complex sociality.

Related: Your Inner FishWhat Dogs Reveal About EvolutionSimple Webcasts on Evolution and GenesTracking Narwhals in Greenland

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