In short, no:

The lack of photos from camera traps for known animals that are presumed extinct - like the Tasmanian tiger, or “unknown” animals (where we have never had a ‘body on the table’ to prove its existence in the first place), is not proof that these things do not exist.

One thing to be said is that it is incredible difficult to prove a species is extinct. To do that you would have to demonstrate that it does not exist anywhere - and it is virtually impossible to do this. Despite this, clearly organisations around the world do list species as extinct. Each organisation will have its own criteria whereby a species qualifies as being listed as extinct. Once upon a time in Australia the criterion was for no definitive record of the species in 50 years. This is the criterion under which the Tasmanian tiger was listed as extinct.

However, even when such criteria are met, it does not mean a species is extinct. Species generally believed extinct but which are subsequently “re-discovered” are often called “Lazarus” species - after a man named Lazarus, described in the Bible as rising from the dead.

So if a species turns up zero photos on camera traps - and has also been listed as extinct - and has had no verified specimen in 82 years (since 1936), can we say whether it is extinct or not? Not really. Most people will agree it is probably extinct. However to answer your question, it is not proven as extinct.

With regards to Bigfoot it is a similar situation, but perhaps even less likely the ‘species’ exists - as we can’t even demonstrate irrefutably that it did exist at some time. Historically, people searching for such species have been termed “cryptozoologists”: “crypto”, meaning hidden, “zoo” meaning animals and “ology” from “logos” meaning “knowledge” - the study of hidden animals. Some time ago I proposed there should be a distinction between searching for those species we have known to exist (like the Tasmanian tiger) and those we speculate may exist (such as Bigfoot) and proposed the term eclipsazoology to describe the study of those animals presumed recently extinct, or on the verge of extinction.

Finally - to the question of why we may not detect a species using camera traps if it is still there. A motion-activated camera trap has an angle of view about 100 degrees wide. The effective distance at which an animal the size of a Tasmanian tiger should trigger the camera is about 60 feet. For the fun of it, that works out to about 290 square metres. Southwest National Park (alone) in Tasmania is 6,183 square kilometres - that’s 6,183,000,000 square metres.

I used to run a business selling camera traps, and government projects using up to about 200 cameras at a time are not unknown. I have also volunteered on Eastern quoll research in Tasmania on a project using a comparable number of cameras across multiple survey sites (one of which - Bruny Island - is just about guaranteed not to have Tasmanian tigers). Overall you will have government work, the devil breeding and research programs, independent and university researchers, thylacine researchers, hunters and hobbyists deploying cameras in Tasmania (not all of them in South West National Park, mind you). Many of the latter will not have more than 10 cameras. Let’s say for argument’s sake we do have an average of 100 people deploying 100 cameras each in South West National Park - that would be 10,000 cameras. I somehow believe the real number deployed in that park will be much less! Still, those 10,000 cameras - if working properly and all deployed simultaneously - are covering an area of about 2,900,000 square metres.

What percentage of that national park have we covered? 10%? No. 1%? Not even. Try 0.04%! That’s four hundredths of a single percent - of that one national park alone, and that is a really conservative estimate of the number of cameras actually out there! I have never had more than 20 deployed at once. I know other researchers with fewer than 100 cameras. I really doubt we have 10,000 cameras out there - and that hasn’t even touched the west coast, the north-west, the central plateau or the east coast and north east.

For what it’s worth, my new strategy is to deploy audio recorders in the hope of picking up a Tasmanian tiger call, then using those results to target a camera-based search. You might like to read my research into recordings of Tasmanian tiger vocalisations which includes a description of the call I heard in 2013 and some audio recordings of calls a colleague and I made in 2017. There is a lengthy analysis of the animal calls recorded in 2017 also.

Pointing toward the location where the first candidate Tasmanian tiger call was heard in 2013.

The above shows a ticker-tape timeline that is part of the analysis of animal calls recorded in 2017.

If you are an Angel Investor reading this, please consider getting in touch via the linked website - and you might be interested in the reason why I believe it is likely the Tasmanian tiger still lives on.

One more set of numbers to consider - at a time when Tasmania had a population of at least 20,000 Tasmanian devils (and it once had about 120,000), my colleague, who was a vet and regularly on the road in country Tasmania, reported seeing a wild devil perhaps once every 6 months. If you read one author’s case for the survival of the Tasmanian tiger - a free e-book named Magnificent Survivor - you will see he estimates a maximum of about 200 to 250 surviving Tasmanian tigers spread around the west coast, north west and north east. If we take the number as 200 - that’s 1 percent of the devil population. So for every 100 devils you see at random, you should see 1 Tasmanian tiger. My colleague was seeing about 2 devils per year at random - meaning he should see a Tasmanian tiger perhaps once every 50 years. And that is exactly what you get - people reporting tiger sightings are generally reporting once-in-a-lifetime sightings. And finally, add to this that the people in Tasmania are largely spread out across the north and down the east coasts and in the central highlands. The south-west has almost no-one. If the tiger persists in the south west, then chance encounters are likely to be far fewer than 1 per 50 years - you might expect 1 in 1,000 people in that area might have 1 sighting in 50 years, and again, these are the sorts of numbers reported.

So it is possible the Tasmanian tiger persists - and do see that link about why I believe it is likely - and a lack of camera trap photos is by no means proof the tiger is extinct.

You can also find out more about Tasmanian tigers - including the examination of the evidence for many sighting claims - at my website Where Light Meets Dark or follow along on Facebook Where Light Meets Dark.