By Michael Peschardt
BBC News, Tasmania
They come out as soon as the sun goes down on the Australian island state of Tasmania.
The winter has now come. The temperature is just above freezing so they are wrapped in jumpers and thick coats as they head out into one of the last great wilderness areas on Earth.
The last known Tasmanian tiger, named Benjamin, died in a zoo in 1936
The bush is thick. It is hard to catch your step. The towering canopy of the eucalyptus trees blots out all but the faintest glow of moonlight.
I have come on this expedition to join Col Bailey and a group of friends on a tiger hunt.
The fact that the Tasmanian "tiger" was officially declared extinct nearly 70 years ago does not deter Col and his fellow tiger hunters one bit.
They are convinced that the nocturnal Tasmanian tiger (Thylacinus cynocephalus), one of the most exotic species to have roamed the Earth, is still out there somewhere hanging on for survival.
Col tells me he saw one 40 years ago and has been looking for another ever since.
"I've smelt one and tracked several since then and you cannot come much closer than that." He smiles to himself as if reliving the experience once more. "They are out there for sure".
There is not a moment of doubt in his mind.
The Tasmanian tiger was once the king of the Australian bush. A carnivorous marsupial, it is in fact no relation to the rest of the tiger family.
It is described as about the size of an Alsatian dog with a head that looks almost too big for its body. Its fur is tan in colour but its back is covered with black stripes.
On seeing it for the first time, European settlers arriving in Australia more than 200 years ago immediately thought it must be some kind of tiger. The name stuck.
Col explains as we stumble over the terrain: "It's not like most predators. It does not possess great speed. Rather than pouncing on its prey, it just runs them down over hours and days. It's more a marathon runner than a sprinter."
The last known Tasmanian tiger died in Hobart zoo of exposure in 1936. The species had been quite deliberately hunted to extinction by farmers incensed at the number of sheep being taken by animals that were seen as nothing more than pests.
There was a bounty on the tigers' heads. Professional shooters were encouraged to go out into the bush. Each pelt they came back with earned them a government-sponsored reward.
But now the hunt has come full circle. Australia's leading news magazine, The Bulletin, is offering a $1m reward to anyone who can photograph a tiger and prove that the species still survives.
Col and the dozens of other long-term hunters say money never has been and never will be their motivation.
The thylacine was a large marsupial carnivore
It ranged widely from Papua New Guinea to Tasmania
Many scientists doubt cloning technology can bring it back
There are clear parallels with the hunt for the Loch Ness Monster in Scotland. The tiger engenders a similar obsession inside the hearts of true believers, but there is a much more solid scientific basis for thinking the tiger really is still alive.
Mena Jones is one of Tasmania's most respected wildlife biologists. She leads a research team at Hobart University and has an open mind about the tiger's survival.
"The longer it goes without a verified sighting, the less likely it is that they are out there."
However, she tells me: "It is quite possible that pockets of tigers have survived. They would be very hard to spot, and they are most likely in areas that are almost impossible for humans to reach. There may well be valleys out in the bush where small colonies are still hiding out."
Tasmania does contain a huge expanse of wilderness. There is hope for the tiger.
Several apparently credible witnesses have claimed to have seen them in recent years.
The only snag is that photographs of the tigers are proving as elusive as the creatures themselves.