how do we determine a species has gone extinct? You’re telling me you looked EVERYWHERE?


how do we determine a species has gone extinct? You’re telling me you looked EVERYWHERE?

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We don’t know for sure. It’s a judgement call based on the lack of sightings of a usually-already-rare species despite searches. Declarations of extinction are occasionally wrong, but usually not (in part because a very tiny population is usually not viable anyway and dies out even if a few endlings are still around).

We’ve looked everywhere that species has been seen before. If it turns out that somehow we missed some, scientists will say so and correct their statements. But in most cases, its pretty easy to check all the places that species has ever been seen before, and confirm there are none left.

Science is about making theories based on all the information you have available, and if new information shows up, adjusting those theories in response.

It’s possible that there are members of a species that we simply can’t find. In fact, there are multiple instances of previously thought extinct species being rediscovered.

But, when scientists are aware of a specific population and that population dwindles to the point that none of them are seen for decades, we assume them to be extinct.

Most species have a specific geographic range and habitat type in which they are usually found. If repeated surveys of those places find no sightings or other evidence, it’s reasonable to assume that the species may be extinct. There’s no need to search everywhere.

Sometimes absence of evidence really is evidence of absence. Coelacanth were thought to be extinct for the entire history of biological study, but nobody had a problem dealing with it when we find out that was a mistaken determination.

All science is *provisional* truth. That doesn’t mean there’s no way to determine that a species has become extinct.