I'll comment on it being mean to bring back the mammoth because the planet is warmer and expecting to get warmer. There are plenty of places they would fit fine in. It getting warmer is 1 or 2 degrees at worst and on average. This carbon issue may get resolved with tech and social changes the future is unknown and a lifetime away.
Mastodon makes more sense to bring back, maybe. They were in a wider variety of climates and they were smaller. I'd love to have a couple grazing in my back woods here on the farm :-)
I’m not so sure you would love that. Mastodons and mammoths are thought to have been rather ferocious, much more aggressive than modern elephants, and probably would not hesitate to attack you. If you are around one, you’d better hide fast.
That isn't exactly clear, and the last of them lived on Alaska's remote St. Paul Island, I believe once a part of the Bearing Land Bridge, at least as late as 5600ya, and some may have survived on the Aleutian Islands as late as 1650BC, and possibly, though unlikely, even as late as 800AD. The last ones were not hunted.
FWIW I believe you're talking about Mammoths, not Mastodons. Similar but not same animal. Mastodons are believed to have gone totally extinct around 10,000 years ago.
There's so much evidence of human hunting of Mastodons, and the timelines are co-related so highly, it's hard to believe we weren't involved heavily in their extinction even if there were other (climate/habitat) related factors.
