What’s the difference between dolphins and whales?

Question

I read that killer whales aren’t whales, they’re dolphins. But I also read that dolphins are whales. I’m so confused. So what are these things?

In: Biology

Answer 1

Well, the difference is at what level of the scientific classification you break them up.

https://en.wikipedia.org/wiki/Taxonomic_rank

They are all cetaceans, which is the infraorder of the scientific classification system for all of these animals. But you go one level down and and now whales and killer whales are in different families.

Killer whales are a member of Delphinidae which is the dolphin family, whereas Grey Whales are a member of the Eschrichtiidae family which includes grey whales and other similar animals.

If you go high enough up in the scientific classes, they are related to Humans as well.