But while scientists in the movie "were so preoccupied with whether or not they could, they didn't stop to think if they should," real-world scientists are now considering the latter. With various "de-extinction" projects in the works right now, researchers at University of California, Santa Barbara (UCSB) have published a paper analyzing the ecological benefits, risks and responsibilities of reintroducing once-extinct species into modern ecosystems.

Bringing back a creature as huge as the woolly mammoth – which hasn't walked the Earth in over 4,000 years – is, well, a mammoth undertaking. Well-preserved remains are relatively common in the Siberian permafrost, but the cells are usually too degraded to be very useful – a stumbling block that's tripped up previous attempts.