Today’s Filter Feeding Whales Had Sharp-Toothed Ancestors

Today we know big blue whales as gentle giants but new studies indicate that it was probably not always this way. While the largest living mammals today eat very small ocean animals—known as krill—whale ancestors actually used to stalk and hunt much larger prey.

Today’s whales are “filter feeders” because they don’t have massive teeth, like sharks and other ocean predators. Instead these whales—called “baleen whales”—filter food through something like a brush: they open their mouths to take in water and food and push the water back out through the baleen bristles.

But, as it turns out, baleen whales did, in fact, at one point, have well-defined teeth. This was not necessarily completely foreign knowledge, but researchers just were not quite sure how ancient whales had used their teeth. Recent analysis of these ancient whale fossils, though, may have shed some new light.

According to paleontologists at Monash University (Melbourne, Australia), 3D scanners can help us to better understand the jaws and teeth of ancient whale. Fossil colelctions all over the world have helped researches to build new models of ancient whale jaws, particularly the ancestors of the southern right whale and blue whale.

And these models reveal very sharp and powerful teeth that would have been quite capable of breaking down much larger fish than krill.

Monash associate professor of biological sciences Alistair Evans comments, “Predators that kill and chew their prey need sharp teeth with cutting blades. By contrast, species that use their teeth as a sieve have blunt teeth with rounded edges that help to filter prey from water.”

He goes on to say, “We found that ancient whales had sharp teeth similar to lions and dingoes so it likely they used their teeth to kill rather than filter.”

Finally, Evans concludes, “Our findings provide crucial new insights into how the biggest animals ever evolved their most important trait: filter feeding. Filter feeding is the defining trait of modern whales — there are few ways in which this unique strategy could have evolved from tooth-bearing, predatory ancestors, and our study firmly rules out one of them.”

The most recent findings have been detailed in the journal Biology Letters.

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