Baleen whales’ ancestors were toothy suction feeders

Modern whales’ ancestors probably hunted and chased down prey, but somehow, those fish-eating hunters evolved into filter-feeding leviathans. An analysis of a 36.4-million-year-old whale fossil suggests that before baleen whales lost their teeth, they were suction feeders that most likely dove down and sucked prey into their mouths. The study also shows that whales most likely lost the hind limbs that stuck out from their bodies more recently than previously estimated.
Paleontology News — ScienceDaily