Today’s baleen whales (Mysticetes) support their massive bodies by filtering huge volumes of small prey from seawater using comb-like baleen in their mouths much like a sieve. But new evidence reported in the journal Current Biology on May 10 based on careful analysis of a 34-million-year-old whale skull from Antarctica—the second-oldest “baleen” whale ever found—suggests that early whales actually didn’t have baleen at all. Their mouths were equipped instead with well-developed gums and teeth, which they apparently used to bite large prey.