This is a scientific American 60 second science. I'm Annie Snead.

Baling whales are the gentle giants of the sea.

Despite their colossal size, they feed on tiny creatures such as krill and zooplankton.

That's because these whales instead of teeth, have bristle-like structures in their mouth,

Bailine, which filters out small critters from big gulps of water.

But the ancestors of bailing whales had a very different diet.

So the oldest, the oldest wells that we know, so these are the ancestors not just of the great wells,

like the blue well and the humpback well but also of all of the

dolphins in the sea today.

They had fairly big teeth.

Felix Marks, a postdoctoral research fellow at the Royal Belgian Institute of Natural

Sciences.

The most common idea is that they ate relatively large fish.

For some of the biggest ones there are some studies that looked specifically

at the wear of those teeth at a microscopic level and they

seem to suggest that they ate almost anything that that they came across. The

point is they they had big teeth that were really sharp and that were even relative to the size of their jaws were relatively large and

so they really were predators. So where did Bailien come from? Marx and his colleagues

set out to answer this question. They analyzed the mouth of a 34 million-year-old

fossil of one of the earliest baleen whales called Jano Cetus denocrinatus,

found in Antarctica. And they concluded that Janusetus had sharp teeth and large gums, but no baleen.

Their findings argue against one of the ideas about how Baleen evolved, that at some point

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