Setting aside the ethical and ecological consequences of reintroducing extinct species, who doesn't want to book a dinosaur safari? Even paleontologists probably nurse a secret desire to ignore the warnings of sci-fi Cassandras and pop out the occasional test-tube Tehuelchesaurus.
Cloning technology today advances in great dinosaurian strides, inspiring some to view dino-clones as inevitable. Stories in 2013 of a Lufengosaurus nesting site containing not only eggs and bones but organic residues further fueled such hopes and fears. Alas, the goop wasn't DNA. In fact, it couldn't have been genetic material, because such molecules maintain a shelf life of around 100,000-200,000 years (1 million at most) [sources: Gannon; Kolata; Mabry; Reisz et al.].
Then again, that spread does place woolly mammoths within range. As the saying goes, God never closes a Jurassic Park but he opens a Pleistocene one. In fact, scientists have sequenced mammoth DNA and recreated its blood using E. coli bacteria, and Russian, South Korean and Japanese researchers soon plan to resurrect the extinct mammal by injecting its DNA into elephant eggs [sources: Boyle; Boyle; Nosowitz]. Researchers also have grown plants from seeds buried by squirrels 30,000 years ago, so they might even treat the resurrected beast to a familiar nosh [source: Boyle].