Should We Resurrect Extinct Beasts?

Maclear's rat (Rattus macleari) is a cute rodent that lived on Christmas Island in the Indian Ocean up until about 100 years ago. Geneticists working with the gene-editing tool CRISPR think the extinct rat can be resurrected, but they wonder if that’s a good idea. Their research appears in the journal Current Biology.

By sequencing the genome of the long-gone rat, the scientists were able to map most of the rodent’s genetic information, and what they lack they believe they can reconstruct using the creature’s living cousin, the Norway brown rat. But that reconstruction, “de-extinction” as they call it, would necessarily involve some guesswork. In this case the missing information pertains to the animal’s immune system and sense of smell, so reviving it poses a risk of creating a compromised organism.

Even if they could de-extinct a healthy rat, should they? The living Maclear’s, which grew to nearly two feet long, was described by British paleontologist Charles William Andrews as “a great nuisance, entering the tents or shelters, running over the sleepers and upsetting everything in their search for food. They seem to eat anything, and destroy any boots or skins incautiously left within their reach.”

Three years after Andrews wrote that in A Monograph of Christmas Island, the Maclear’s was extinct, probably done in by a disease brought to the island by black rats (Rattus rattus) that had stowed away on ships.

Even the authors of the new study are wary of playing God. “The science of de-extinction is fantastically interesting, but the proposition that we've lost species and so we'll just bring them back is not thinking it through with respect to animal welfare,” co-author Ross MacPhee told NBC News.

Currently there are projects underway to resurrect the wooly mammoth and the passenger pigeon. Ready or not, it’s coming.

Photo credit: Joseph Smit / Zoological Society of London (1887)