The Frozen Zoo is a fascinating effort underway at the San Diego zoo for many, many years. The advantage of the zoo is that animals long dead, their genes apparently lost to their species forever, if they were collected and preserved in the frozen zoo and if the technology for their species has been developed can be brought back. They can be re-introduced if there are still some individuals alive, some females. This does not mean that you can take pieces of a mammoth someplace and bring it back.
