It's important to understand the difference between extinct and critically endangered. Extinct means a species no longer exists anywhere in the world. Critically endangered means a species is at extremely high risk of extinction in the wild.
Red wolves were once abundant throughout the southeastern United States, but their numbers have declined dramatically due to habitat loss, hunting, and interbreeding with coyotes. Estimates suggest that there were only around 100 red wolves left in the wild in the 1970s when they were officially listed as endangered.
Thanks to captive breeding programs and reintroduction efforts, their numbers have since increased, but they still remain extremely vulnerable.