Orcas are called killer whales due to the fact that they are the top predator in the ocean. They are the hunters, not the hunted. They eat almost anything and everything they â¦ can find including other whales.ou can thank the Greeks and the Romans for the name Orca, and the early Spanish sailors for the term Killer Whale. Ancient Romans originally applied the name Orca to these animals, possibly borrowing it from the Greek opue. One other thing, they are not really whales, but a type of dolphin.