Whales Took an Evolutionary Leap Forward

Eons ago ancestors of whales made a major leap forward in evolution of their mouths. Whales living today can filter-feed in large amounts because the lower jaw is flexible in movement.

Ancient fossils such as Janjucetus hunderi do not have such a mobile lower jaw. The development of this attribute probably initially evolved to consume large living prey. It began with a wide upper jaw and normal teeth - no comb filters. Erich Fitzgerald from the Museum Victoria in Melbourne has created a family tree showing whale evolution.

The way whales feed is unique. It is believed that sucking when feeding still takes place, a left over from the days of the wide upper jaw.

A big question is why whales went back into the sea in the first place.
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