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> > David: The way some whales feed they don't need teeth:
> > 
> > https://phys.org/news/2018-11-whales-lost-teeth-evolving-hair-like.html
> 
> For some reason the excerpts didn't publish. From a different article:
> 
> https://www.newscientist.com/article/2186912-prehistoric-whales-used-to-simply-suck-their-food-out-of-the-ocean/?utm_medium=NLC
> 
> Whales were once all toothed predators. Around 36 million years ago, a group of them evolved to lose their teeth. We don’t know what drove that evolutionary trend, but it ultimately gave rise to today’s filter-feeding whales, including blue whales and humpback whales, that use baleen bristles in their mouths to remove tiny prey from the water.
> 
> Scientists haven’t been able to precisely reconstruct what happened during whales’ transition from teeth-bearing to filter-feeding – but they had assumed that the filter-feeding system emerged before the whales lost all their teeth.
> 
> ***
> 
> Using CT scans, the team found the extinct whale (Maiabalae nanesbittae) had no alveoli – teeth sockets. It also had a different mouth structure than baleen-bearing whales, meaning it had no ability to filter-feed either.
> 
> “[The whale] represents a surprising intermediate stage between modern filter-feeding whales and their toothed ancestors,” Peredo says. “Our study makes it very unlikely that teeth and baleen existed at the same time in the same animals.”
> 
> Peredo suggests baleen might have appeared 23 million years ago, about 10 million years after whales lost their teeth.
> 
> But how did M. nanesbittae capture prey? Peredo says this whale was probably a suction-feeder like modern salmon and trout. The whale has an enlarged bone in the back of its mouth, resembling those observed in suction-feeding fish. Such bones help the mouth muscles generate a strong sucking force.
> 
> The transformation from a biter to a suction-feeder then into a filter-feeder also tells us about when whale diets changed. Sucking and biting are techniques that work best when the animal aims to take one target at a time, whereas filter-feeding targets bulk quantity of tiny organisms.
> 
> “There’s a good chance that [filter-feeding] is more energetically efficient,” Peredo says. “It seems to be a successful body plan for marine mammals.”
> 
> Comment: When a mammal enters a new environment to live the changes have to be very complex and enormous. Just hopping into the water doesn't work. Losing teeth and gaining a filter system isn't done stepwise. It has to be designed.