All whales use predation, just not in how we commonly think of it, such as with the great Blue Whales, which eat Krill or Sperm Whales, which hunt Giant and Colossal Squid. All whales eat some form of animal, thus making them predators.
A killer whale is actually an apexial predator. There is no predator for them.
no
Probably Humans or a killer whale
hobo
a killer whale
Sharkes and people
The sperm whale.
Believe it or not, the largest natural predator of a moose is the killer whale or orca.
to krill but other then that ... no not really
mostly shark rarely whale
Whale
only if you're a plankton