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. But new evidence 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. Their had well-developed gums and teeth, which they apparently used to bite large prey.