(n.) a species or zoological taxon that appears to have come back from extinction, but is later found to be a different creature
Sometimes, words just make you smile. Like this one.
So a Lazarus species is one that comes back from the dead, and an Elvis one that only appears to do so. The story here will be a familiar one. According to the Gospel of John, Lazarus of Bethany was brought back to life by Jesus, four days after death—so a Lazarus creature is one that has been declared extinct, but is later found to have clung on to survival and seemingly come back from the brink.
The example we gave on Twitter, the brilliant takahe bird of New Zealand, is just one of a number of these Lazarus species from around the world. In 2018, for example, a camera trap on an island off the coast of Tanzania snapped a picture of the first Zanzibar leopard to have been spotted in 16 years. The same goes for the Vietnamese mouse-deer, which was caught on a camera trap in 2019 for the first time since 1990.
Incredibly, some Lazarus species drop off the map for centuries, not just decades. The woolly flying squirrel, for instance, was previously only known to science thanks to a dozen furs and pelts bought at a market in Pakistan in the nineteenth century. Believed to have long ago been hunted to extinction, a handful of live specimens were caught during a Wildlife Conservation Society expedition to Kashmir in 2004; the species is now officially listed as endangered, not extinct.
Even more extraordinary, the Machu Picchu arboreal chinchilla-rat was believed to have gone extinct in the sixteenth century, before being found living perfectly well in the high-altitude rainforests of Peru in 2014. And the Caspian horse, or khazar, is the only surviving relative of the very first horses ever domesticated by humans, and has a lineage dating back more than 5,000 years. Presumed to have long been bred out of existence, a population of khazars was discovered among a group of peasant farmers living in Iran’s Alborz mountains in 1965.
Sometimes, however, a creature that appears to have resurrected itself turns out to be something quite different altogether. In 1993, a palaeobiologist named Dr Douglas H Erwin described for the first time how some ancient creatures appear to survive mass extinction events, and then reappear in the fossil record as if entirely unaffected by them at a later date. On closer inspection, Erwin explains, these apparent Lazarus species sometimes turn out to be different creatures, and are entirely unrelated to the earlier pre-extinction event species. Rather than demonstrate a species surviving in small yet robust enough numbers to eventually flourish again, these creatures ultimately exhibit an evolutionary phenomenon known as homoplasy—in which an observable physical attribute develops among two distinct creatures, despite them having no immediate common ancestor.
Such a distinct phenomenon, of course, demands a distinct name. Over to Dr Erwin:
New terms should be proposed with caution when they describe a particularly important phenomenon, and never in jest. In addition, terms should be short and memorable if they are to achieve any currency. [University of Chicago professor of geophysical sciences David] Jablonski’s Lazarus taxa meet all of these criteria, and we believe the new phenomenon outlined above does as well. Rather than continue the biblical tradition favored by Jablonski, we prefer a more topical approach and suggest that such taxa should be known as Elvis taxa.
Why Elvis? Well, not only has Mr Presley himself long been claimed to have survived his 1977 demise, but as Erwin also explained, the term is meant to allude to “the many Elvis impersonators who have appeared since the death of The King.”
So long as there’s someone willing to imitate you, then, it appears you really can live on after death.