At 98 feet long and 200 tons, blue whales are by far the largest animals on Earth. To get that massive, blue whales need to eat millions of calories. A day. They feed exclusively through baleen filter feeding and can gulp down nearly 8,000 pounds of krill per day. Baleen, a substance used for feeding found only in whales, is made out of keratin–the same stuff as human hair and nails.
(From Forbes / by Shaena Montanari)– These ragged plates at the opening of the mouth allow whales to filter thousands of gallons of water to strain out literally tons of krill to eat. Baleen makes a relatively recent appearance in whale evolutionary history, and now it seems it may have appeared more recently than previously thought according to a new study by paleontologist Felix Marx of Museums Victoria and Monash University and an international team of colleagues in the journal Memoirs of Museum Victoria.
Although there are 15 living species of filter feeding baleen whales, earlier in their 50-million-year evolutionary history, whales just had teeth for chomping. Baleen does not fossilize easily, so paleontologists have been left wondering when and how exactly whales made the transition from teeth to baleen. A new 25 million-year-old fossilized whale skull from Washington may hold the answer.
The yet-unnamed species of extinct whale nicknamed “Alfred” is a member of a group called aetiocetids. Aetiocetids lived during the Oligocene (33-23 million years ago) and are early whales that had teeth for eating prey larger than krill, the preferred diet of modern baleen whales. It has typically been thought aetiocetids may have had both baleen and teeth, but this is difficult to prove without the presence of fossilized baleen.
The tooth wear patterns on the new fossil seem to tell a strange and unexpected story. Almost all of the tooth enamel on the back side of the tooth, the part that touches the tongue, has been scoured away. All of the teeth are worn in this very peculiar fashion. Marx and colleagues noted that it looks most like tooth wear seen in other marine mammals that feed by sucking water and food through their teeth rather than biting at it. Walruses are known to feed in this manner and often have similar looking horizontal striations on the enamel surfaces of their teeth.