Question: is it true that the biggest dolphin is the killer whale? if so why is it called a killer whale not a killer dolphin? :s

Valeria Senigaglia answered on 19 Jun 2012:

Is true, killer whales are dolphins.

I agree with you that the name is confusing, is not even the only case, in fact pilot whales, melon-headed whales, false killer whales, etc are all examples of dolphins that are called whales.
The reason is that the first fishermen/scientist who described these species called whales whatever animals bigger than 3 meters and black in color.
The actual latin name of these species are less confusing 🙂