Perucetus

Perucetus is an extinct genus of early whale from Peru that lived during the Bartonian age of the middle Eocene. With an estimated length exceeding 17.0–20.1 meters (55.8–65.9 ft) and weight ranging from 85–340 t (84–335 long tons; 94–375 short tons), Perucetus may have rivaled, if not exceeded, the modern blue whale in weight. This is in part due to the incredibly thick and dense bones this animal possessed, coupled with its already great size. The ecology of Perucetus, however, remains largely mysterious. Based on the fossils, it was likely a slow-moving inhabitant of shallow waters. Its diet can only be speculated upon, but one suggestion proposes that it may have fed on benthic animals like crustaceans and molluscs that live on the ocean floor. Only a single species is currently known, P. colossus.