Once upon a time (in July), beneath the water-logged soil in Victoria's Dandenong Ranges, a perfect tiny crayfish lived in a burrow on the edge of a perfect gurgling stream.

The crayfish was only as big as a tea bag and didn't like company.

It played dead when it was disturbed, but despite its best efforts, the biggest predator of all (us) started to take notice.

Above the ground was a world of mountain ash and glistening tree ferns, but underground, the Dandenong crayfish burrowed, unaware it was about to become the lead character in a rainforest fairy-tale where a scientist falls in love with a cray.

The cool temperate rainforest in the Dandenong Ranges is characterised by towering mountain ash, southern sassafras, and tree and ground ferns. ( ABC: Jo Khan )

In this magical rainforest the mist lingers low in winter, and the birds wake slowly.

The cold, still air is broken by the call of a male lyrebird practising his mating song; a cackling kookaburra and the cry of a cockatoo — or maybe just that same lyrebird running through his songbook of mimicry.

And, if you look closely, you can see tiny holes in the damp soil.

Tiny holes underfoot often go unnoticed. ( ABC: Jo Khan )

Residents in the Dandenongs might notice the small holes in their gardens, but few would know there could be an endangered animal hiding in them.

This is changing though, because the Dandenong burrowing crayfish has captured the attention of scientist Diane Crowther from the Athur Rylah Institute.

Scientist Di Crowther is all smiles when it comes to talking about the little burrowing crayfish hiding in the Dandenongs. ( ABC: Jo Khan )

Dr Crowther began investigating the burrowing crayfish in 2011, nearly 30 years after the last records of the Dandenong burrowing crayfish were made in 1982.

She soon fell in love with the crayfish's hermit-like nature.

"I love the Dandenong burrowing crayfish because it's so secretive," Dr Crowther said.

"No one even knows they're there!"

She admits they're no charismatic koala, but they still hold their own in a rainforest full of awe-inspiring animals — and plants.

"They're not furry, they're not feathery, but they're amazing little creatures," Dr Crowther said.

"And once people find out about them... people love them."

The rainforest is home to many animals, including this boobook owl. ( ABC: Jo Khan )

Unlike freshwater crayfish and yabbies, these burrowing crayfish live underground and are terrestrial species.

There are 35 different species in Australia, and many of them live only in the one place and are specialists in a particular habitat.

In the Dandenong Ranges there are two species of burrowing crayfish, who politely keep out of each other's way — the Dandenong burrowing crayfish and the tubercle burrowing crayfish.

The tubercle burrowing crayfish is slightly larger and more orange than the Dandenong burrowing crayfish. ( ABC: Jo Khan )

Of the two, the tubercle burrowing crayfish is more common, and prefers to burrow further up the slope away from the creek.

Dr Crowther said the tubercle crayfish's feisty nature is a reflection of its preference for burrowing more out in the open.

"There's this habitat separation between the two crayfish, and a behaviour difference too," she said.

"The tubercle crayfish will make threat poses with its claws, whereas the Dandenong burrowing crayfish will just play dead."

Crayfish traps are used to capture the crays. The traps are put out in the afternoon and collected in the early morning. ( ABC: Jo Khan )

The Dandenong burrowing crayfish's secretive lifestyle has prevented it from being well studied. So few have been found it's now considered endangered.

To try and narrow down the crayfish's range, Dr Crowther and her team of volunteers deployed specially made 'you-beaut' hardware traps along some of the creeks on private property in the Dandenongs.

The traps are made of piping that acts as an extension of the burrow, enticing the crayfish into the cool, dark enclosure.

The two tiny crayfish fit nicely into the fairy-tale-like world that is the rainforest undergrowth. ( ABC: Jo Khan )

The traps are left in place overnight and checked the following morning.

When Dr Crowther unscrews the cap on one of the traps and peaks into the tube, the volunteers huddled around her hold their breath.

The first crayfish caught was a tubercle burrowing crayfish, not a Dandenong burrowing crayfish. ( ABC: Jo Khan )

Out of the trap came a tubercle burrowing crayfish with claws flailing. If it wasn't so tiny and cute it might be quite terrifying.

As soon as Dr Crowther tried to pick it up, it pinched her finger.

"Now the feistiness is coming out," she said.

The orange claws of the tubercle crayfish are covered in fine hairs. ( ABC: Jo Khan )

"That makes them scary and big to potential predators, when they put their claws out like that."

It might not be the crayfish the team were hoping to catch, but the tubercle burrowing crayfish was, for many of the volunteers, the first burrowing crayfish they'd ever seen.

While they don't stand a chance against humans, Dr Crowther does wonder if the crayfish are aggressive or defensive toward each other. ( ABC: Jo Khan )

Unlike yabbies, burrowing crayfish have narrow bodies, as if they've been squished between two hands.

Yabbies and freshwater crayfish on the other hand, look a bit more as if they've been flattened beneath a boot from above.

The first crayfish might not have been a Dandenong burrowing crayfish, but it was a great sign that the traps were working. ( ABC: Jo Khan )

One of the volunteers found another crayfish in a trap.

It was in a trap closer to the creek, leading Dr Crowther to think it could be the elusive Dandenong burrowing crayfish.

The dark colour of the claws indicates that this time, they caught a Dandenong burrowing crayfish. ( Supplied: Arthur Rylah Institute )

And it was!

"This is brilliant! Well done everyone, it's fantastic," Dr Crowther said.

The Dandenong burrowing crayfish is much smaller and darker than the tubercle burrowing crayfish.

And unlike the tubercle burrowing crayfish, it's clearly not a fighter.

Fight, or flight... or freeze? ( Supplied: Arthur Rylah Institute )

"It's playing dead!"

"This is what they do," said Dr Crowther. "This is the behaviour difference."

The Dandenong burrowing crayfish seems so much more subdued than the tubercle burrowing crayfish. ( ABC: Jo Khan )

Only one Dandenong burrowing crayfish was found in the surveys, but it was the first one ever found on private property, which is promising to Dr Crowther.

"It's a gap in the distribution," she said.

"Most of our surveys have been in national parks and public areas, but now with the support of the local community groups we have been able to get access to these private properties.

"That's a key bit of information we're missing."

And because the locals are opening up their properties to Dr Crowther and the volunteers, they too are learning more about the crayfish and its environment.

"You get someone's attention on one thing, and then they really start looking around," Dr Crowther said.

"And that's what we need to do to protect these precious habitats and all the species within them."