Two follow-ups on this topic --

Extinct ibex is resurrected by cloning
An extinct animal has been brought back to life for the first time after being cloned from frozen tissue.
http://www.telegraph.co.uk/scienceandtec...by-cloning.html

(so what's appropriate for Mastadon hunting, a .600 Nitro?)

Wild boar 'should return to British woodlands'
Wild boar should be allowed to regain their natural place in the UK's woodlands, the Wildwood Trust urged today as it welcomed the birth of three new piglets to its resident boar couple.

http://www.telegraph.co.uk/earth/wildlife/4420402/Wild-boar-should-return-to-British-woodlands.html