In order to determine how often extinct species had been rediscovered, University of Queensland scientists Diana Fisher and Simon Blomberg created a dataset of 187 mammal species that have been reported extinct, extinct in the wild, or probably extinct since 1500, as well as those which have been rediscovered. They also looked at historical data on the threats that caused species to become extinct — or brought them close to it — including habitat loss, introduced species and overkill by humans.
It turns out that rumors of the extinction of more than a third of these species have turned out to be premature, the scientists report in Proceedings of the Royal Society B Sept. 29. At least 67 species — a little more than a third of those presumed to be extinct — were later found again. And in most cases, these were animals that had been hardest hit by habitat loss.
As an example, Fisher cites the Malabar civet, which was thought to be extinct due to habitat loss in 1929 but survived in marginal areas at least until 1987 when it was last seen on a cashew plantation. Unfortunately, that animal was killed by villagers, and no more have been seen since.
The team found species that were relatively sparsely distributed over a larger range were more likely to turn up again. But mammals of any particular evolutionary group or body size weren’t more likely to be rediscovered.
The study also found that if humans and invasive species were the culprits in their demise, they are probably really gone. But, if extinction was chalked up to habitat loss, then a few individuals may be restricted to a very small area.
A few observations on this study. First, if it’s valid then that tells us we may find a few individuals remaining. That does NOT mean they will survive because you need to have a certain number to ensure genetic diversity to survive.
This really means little in the realms of cryptozoology where some people investigate reported sightings of extinct creatures. Humans put out of business the interesting species like the moa and thylacine (pictured here). So, it’s unlikely they survive after all this time. (But, not impossible.) Regardless, this says NOTHING about the possibility of Bigfoot or relic hominids. As the time span gets longer, the odds of survival get ridiculously small. Essentially, biologically zero.
But it does bode better for species like the ivory-billed woodpecker.
We shall see. But, try not to get your hopes up. If a species is too rare to be regularly found, it probably won’t limp along for much longer. Extinction is both natural and man-assisted. Sad but true. All species will die out. Eventually.
Note, I don’t have access to the main journal publication cited but Brian Switek is a good source for interpretation. It is a small study though. Not sure what real world extrapolation it really has. Again, don’t read too much into it.