Today , baleen heavyweight have a report for being gentle giants , butnew researchshows this was n’t always the case . In fact , the tooth of ancient whale far more closely resemble those of an African king of beasts than those of 21st - century blue whales .

whale can be divide into two categories : those with dentition and those with baleen , a problematical but flexible material made of keratin that work a chip like a combing to filter quarry from the   water . In the first category , you ’ll find killer whale , sperm hulk , and beluga whales .   In the moment , you have blue heavyweight , southern right whale , and humpbacks .

How baleen get has been something of a enigma . Some scientists advise that ancient baleen whale   ate   food   in the same means crabeater seals and leopard seals do today . That is their   tooth   were mold   to mold   a zigzag - zag when shut . This would have worked like a sieve , entrap food inside while letting piddle move in and out of the lip .

But this hypothesis has now been expose by a field bring out inBiology Letters .

Paleontologists at Museums Victoria and Monash University in Melbourne , Australia , create 3D digital model to liken the fossilized tooth of a prehistoric heavyweight ( ajanjucetus ) with   the teeth of modern - solar day mammals . They unwrap that the teeth of ancient baleen whales were much sharper than those of baleen heavyweight today , and are   almost as knifelike as an African   lion ’s . This , they say , suggests that the ancient beast   were not patrician whale , but predators who used their teeth to wipe out and masticate their prey .

" These consequence are the first to show that ancient baleen whales had passing knifelike teeth with one function   –   trim down the physical body of their prey,“explained Erich Fitzgerald , Museums Victoria ’s senior curator of vertebrate   palaeontology . " Contrary to what many people thought , whales never used their tooth as a sieve , and rather evolved their signature filter alimentation technique later   – peradventure after their tooth had already been lost . "