I think a Sperm Whale is the largest predator ever to swim the oceans. I don't believe plankton eaters are predators but filter feeders.
The largest theropod as well as the largest terrestrial predator yet known is Spinosaurus aegyptiacus, with the largest specimen known estimated at 16–18 metres (52–59 ft) in length and around 7–21 metric tons (8–23 short tons) in weight.[57]
T-Rex was probably just about the baddest.
http://en.wikipedia.org/wiki/Largest_pre...
What was the largest land predator ever to walk the Earth and what was the largest predator ever to swim the seas?
