It seems you may be confused. There are some species of whales that have gone extinct, but killer whales are a thriving species.
Here are some reasons why you might have heard otherwise:
* Misinformation: Sometimes false information about animals spreads, especially online.
* Specific populations: While killer whales are doing well overall, there are some populations that are threatened or endangered due to factors like pollution, habitat loss, and fishing.
* Confusion with other animals: There are many different species of whales, some of which are unfortunately endangered.
It's important to be critical of information and check your sources. The best way to get accurate information is to consult reliable sources like scientific journals, reputable wildlife organizations, and government agencies.