One of the great mysteries in marine research is how whales developed baleen, the unique array of plates and bristles that allow them to filter thousands of pounds of krill and plankton every day.
Because baleen whales’ ancestors had teeth, it was thought that some ancient whales began to filter feed using their teeth like a sieve. Over time, the filtering behavior would have caused whales to evolve baleen to fill in the gaps of their teeth before replacing them entirely. Another theory was that a transitional group of prehistoric whales fed with both baleen and teeth for a period of time before losing their teeth. But both of these long-held ideas might have been proven wrong by a new discovery that suggests a different evolutionary progression from teeth to baleen.
Paleontologist Carlos Mauricio Peredo and a team of researchers say the fossil of a 33-million-year-old whale from the Oregon coast lacks both teeth and baleen. This suggests that some ancient whales first lost their teeth and then developed baleen later on, they say in a paper published in Current Biology this week.
