How does an extinct species comes back in the wild?

Question

I was browsing through reddit and I found a picture of a European Bison, and it was said that that species was once extinct.
So I wonder, since a certain specie that goes extinct, loses their ability to reproduce, how does an extinct specie comes back?

Thanks!

In: Biology

Answer 1

There are cases where a species has re-evolved itself into existence ([https://www.livescience.com/65477-flightless-bird-evolves-twice.html](https://www.livescience.com/65477-flightless-bird-evolves-twice.html))

But more likely it was due to the conservation efforts mentioned in another comment where zoo specimens were bread and released back into the wild.