A 30 million year-old fossil whale may not be the heaviest animal of all time after all, according to a new analysis by paleontologists at UC Davis and the Smithsonian Institution. The new analysis puts Perucetus colossus back in the same weight range as modern whales and smaller than the largest blue whales ever recorded. The work is published Feb. 29 in PeerJ.

To crack the code of whale communication, scientists rely on underwater microphones called hydrophones to gain access to the animals’ soundscapes. In aqueous environments, sound travels about five times faster than it does in air. What’s more, acoustic waves face less dissipation in water, traveling farther and differently than in air. New advances in hydrophone technology spearheaded by a UC Davis scientist are giving us an unprecedented view into the lives of whales.