Reintroducing it into the wild? How is that a good idea?
Something something climate change? They went extinct because the pre-Industrial climate shifted. It doesn't even make nonsense; it's just word salad.
"These islands were full of mammoth bones, and the quantity of tusks and teeth of elephants and rhinoceroses, found in the newly discovered island of New Siberia, were perfectly amazing, and surpassed anything which had as yet been discovered.... Hedenstrőm started from Ustyansk, near the mouth of the Yana, on March 19th, 1809, taking with him two companions, and for three consecutive seasons they examined the islands.
Hedenstrőm found that the quantity of fossil ivory on the first island found by Liakoff (i.e., Liakoffs Island) was so enormous, that, although the ivory diggers had been engaged in collecting ivory from it for forty years, the supply seemed to be quite undiminished."
https://malagabay.wordpress.com/2019/08/19/alaskan-muck-ivor...
It's a long and forgotten story (from more than a century ago)... these might help: