Re: unsure what to say
Mcfly is right. Natural history is a fluid process, not a static one. It's all too easy for well-meaning people to get the idea that the natural environment and set of species that exist right now are somehow the "correct" ones, and we should be very careful that nothing changes.
Certainly little would be harmed by a population of mammoths in zoos or reservations. Maybe replanting them in places like Siberia or northern Canada would work now that people have other things to eat.
And hell, if we raise up an extinct species that takes over the world and wipes us out, in Mother Nature's big picture that's natural selection, too.