Joshua Van Dyk will happily abseil into a pitch black cave, or squeeze through crevices no one has ever gone into before.

"It feels comforting," he laughs, "I don't mind tight spots." 

Although that might sound terrifying, he's had plenty of experience.

He's from a multi-generational caving family in Buchan, Victoria who have been working with palaeontologists at Museums Victoria since the 1990s to investigate caves in their local area. 

And he's also part of a team of scientists, rangers and citizen cavers who recently uncovered a 50,000-year-old short-faced kangaroo skeleton in an undisturbed cave in East Gippsland. 

The fossil of Simosthenurus occidentalis is one of the most complete found in Australia, and was extracted after more than 58 hours of caving in a two-year period.

"The rarity of finding a single, near complete example of an individual like this [...] it's the dream for any palaeontologist," said Tim Ziegler, Museums Victoria vertebrate palaeontology collections manager. 

"The last and first time a comparably complete example of this species of kangaroo was found was in the mid-1970s. It's been nearly 50 years." 

The discovery highlights the role of non-scientists in finding and extracting fossils like this — particularly recreational cavers who dig out, abseil down, and crawl through caves in their spare time.

What was found? 

Scientists uncovered 150 bones of the extinct kangaroo species in Nightshade Cave near Buchan.

The skeleton has 71 per cent of its bones, which makes it the most complete fossil skeleton ever discovered in a Victorian cave. 

"Most of the [bones] that are missing are very small elements, like knuckles from the hands, and small bones in the feet," Mr Ziegler said. 

The short-faced kangaroo specimen found by the researchers is a juvenile, but it may have weighed as much as 80 kilograms.

An adult of the ancient species would have been about the size of a large grey or red kangaroo today, but would weigh twice as much.

Researchers have suggested that this heavier structure might mean that S. occidentalis and other species of short-faced kangaroos may not have hopped, and instead walked in a similar way to humans. 

"The entire skeleton — from it's shoulders and it's arms, through it's backbone to his hips and it's legs and it's tail — tells you something very different from what a living kangaroo tells you," Mr Ziegler said.

To find out the age of the specimen, the researchers sent a small sample to the Australian Nuclear Science and Technology Organisation (ANSTO) to radiocarbon date the remains.

"We tried first to extract any collagen from the bones but we found it was quite old," said Vladimir Levchenko, a research scientist at ANSTO who dated the specimen.

"But there are other ways to date things. In particular, with this kangaroo, it was associated with a layer of charcoal. In Australia, fires are quite common, so charcoal is very present in the Australian environment."

Charcoal just above the kangaroo was found and dated, providing a minimum age for the specimen of 49,400 years old.

How was the kangaroo extracted? 

The fossil was first noticed in July 2011, when a group of five recreational cavers, including Mr Van Dyk, opened a cave near Buchan in East Gippsland. 

According to him, the area was almost completely closed off, with "just a tiny depression and a tiny hole about the size of a 50 cent piece".

After about 20 hours of digging, the team exposed an entrance that allowed the group to abseil into the cave about 10 metres down, before belly crawling through a tight U-turn crevice into the cave.

At the time, only a small amount of the skeleton was exposed, and the remainder was under a large boulder, but the team let Museums Victoria know there was something there.

"The impression at the time was that it would be difficult, maybe impossible, to attempt the retrieval of the rest of it," Mr Ziegler said.

Being in a secluded cave, it was thought the bones would be safe from the elements, but during a follow up visit over 10 years later, the team discovered the fossil — which was not just a few bones, but an entire skeleton — had begun to decay. 

"We hadn't acquired the direct dating, but we knew from national records that it had to be at least 45,000 years old," Mr Ziegler said.

"What a tragedy it would be if it had just decayed away after all of that time."

Over the next two years, Mr Ziegler worked with rangers, cavers and scientists to get into the tight spot, and painstakingly extract the skeleton piece by piece. 

"Carefully cleaning and exposing bones in place, documenting, collecting samples from sediment, and individually collecting, packing and removing each element from the cave," he said. 

"[You're] working at the end of your reach into this tiny little crevice. It's a very uncomfortable place to be, particularly in your all-in-one caving suit and helmets and lights.

"It was a really physically challenging process."

What do cavers do?

It's not normally scientists or museum collection managers who shimmy through caves to find bones.

Instead, it's citizen cavers, like Mr Van Dyk, who explore and chart cave systems during their spare time, mostly on weekends and days off.

"Especially with new caves, no one's ever been there before. You're the first one," he said.

"You don't know what's around the next corner, or down the next hole."

Gavin Prideaux, a palaeontology researcher at Flinders University who was not involved in the research, said cavers were "absolutely critical" to finding new fossils. 

"Often times, at least in the first instance, you're relying on the people with eyes on — or under — the ground reporting finds to you, even the bad things," Professor Prideaux said. 

"They're not usually in contexts where you can just casually wander in."

He suggests cavers take photos of the bones instead of touching them, as the location and surrounding area near the bones can also hold valuable information.

Most of the time the bones will likely be from a recent animal, and aren't helpful for researchers, but occasionally you strike fossil gold.

"Sometimes in cave deposits — the Naracoorte Caves are a good example — you get thousands upon thousands of bones, but it's all different individuals jumbled up," Professor Prideaux said.

While cavers are some of the few groups who have the speciality knowledge to be able to get into these difficult environments, they're not doing it for the bones. 

The Victorian Speleological Association (VSA) says their aim is to "explore and chart the extensive cave systems in Victoria".

Wayne Revell, the president of the VSA, said although most scientists who need their help end up catching the caving bug themselves, they do sometimes help non-caving scientists dig out, rig up, and enter caves safely.

"A lot of cavers are volunteers and are just doing it for the fun of caving. Whether there's a paper released or not, whether it mentions the cavers or not, I don't think it's a big deal, although it might be for some," Mr Revell said. 

"Tim [Ziegler] has been really good with this. He's put my name on papers and I thought, 'wow, I hardly did anything. I was just there for the enjoyment'." 

As an example of a scientist who caught the caving bug, Mr Ziegler is now the vice president of the VSA. 

How scientists will use the fossil 

While museum-goers are likely accustomed to seeing full skeletons of dinosaurs and ancient Australian mammals, they're not actually what they seem. 

"Most fossil skeletons that are put on public display in museum galleries are replicas, and replicas are often composites," Mr Ziegler said. 

This means that usually one ancient animal was not the source of all the bones in a full skeleton. Instead, multiple fossils are brought together to design one creature.

This is fine for public display, but it's not as useful for scientists, who may need to investigate how certain bones change over time or location.

Megan Jones is a PhD student looking at the vertebral column (known as the backbone) in both extinct and living species of kangaroo to better understand how they walked or hopped. 

"I need to find specimens which have fairly complete vertebral columns, which the Simosthenurus occidentalis skeleton is a very good example of," Ms Jones said.

"Vertebrae are smaller bones and there's a lot of them, so the chances are they're going to get damaged."

Ms Jones also said small bones like vertebrae are sometimes not noticed among the other, more recognisable bones.

Dozens of the small bones that form the vertebral column need to be found, compared to just one easily recognisable skull. 

"It's really a challenge to find good specimens," she added.

The S. occidentalis fossil will be on public display in the Research Institute Gallery at Melbourne Museum from June 24.

A few years ago, Charles Duhigg thought he was an excellent communicator.

He was a journalist. He had a Pulitzer Prize. His job was literally to communicate.

Then he became a manager at the New York Times newspaper, where he'd been working.

"I discovered I had no idea what I was doing … I would fail to hear what people were really trying to tell me [and] I couldn't get across what was important to me," he tells ABC RN's All in the Mind.

"I really wanted to connect with these people and I wanted us to work together as a team. I couldn't figure out what was going wrong."

So he began to investigate. He interviewed people he deemed to be "supercommunicators": CIA recruiters, NASA psychologists, researchers and more.

He learned these people weren't born having great conversations and communicating effectively; they'd just honed a set of skills — and Duhigg says anyone can learn them.

More questions, more laughing

There are several habits supercommunicators share, Duhigg says.

In conversation, they tend to ask 10 to 20 times as many questions as the average person. They also laugh more, to show they like what you're saying.

And they ask deep questions about a person's values, beliefs or experiences. For example, if you've just asked someone what they do for a job, a deep follow-up question could be, "Did you always want to be/do that?" Or, "What do you love about your job?".

"What I'm really asking you to do is talk about your experiences, what brought you to this place, your beliefs," Duhigg says.

"It's really powerful."

Supercommunicators also use a technique called "looping for understanding".

That involves asking a question, listening to the response, repeating back in your own words what you've heard the other person just say and, finally, asking if you got it right.

"What's important is to prove to you that I'm listening," Duhigg says.

People want to feel heard

The power of listening is something Beverley Wang knows a lot about.

As host of ABC RN's Stop Everything! and co-presenter of Life Matters, her job is to nurture and lead powerful conversations every day, including those which are personal or political — and everything in between.

Even when she might disagree with what someone's saying, she's learned the power of letting that person know she's listening.

Again, reflecting back what's been said to her — which doesn't necessarily mean showing agreement — is an important way of doing that.

"I think it's very validating for people to feel like they've been heard," Wang says.

"That's what people want; it's a very fundamental, universal thing.

"Sometimes people trade opinions or views on something, and disagreement can be taken personally. It's understandable, because you're kind of putting a piece of yourself out there."

But Wang's job has taught her that being less reactive is more productive, and that there's power in asking deeper questions, like: "What do you mean by that?"

"It's learning that middle path of eliciting more from others — not necessarily making it about yourself — and taking time to listen, and not being quick to anger."

She says open-ended questions are really important to open up conversations on difficult topics in particular. That's asking questions like: "What do you think about that?' or, "That's interesting, tell me more" or "Why do you think that?"

Wang also believes there is huge value in letting people "have their pauses" in a conversation, and not jumping in to fill a silence — something a lot of people struggle to resist.

"Let the silence sit there if it needs to," she says.

"Don't rush to fill the space. You're allowed to think — in any situation. As I get older I'm also like, I don't have to have an opinion or a thought or a reaction to this right now. I'm actually going to come back to this one tomorrow.

"It's OK to slow down the pace of the conversation."

Make sure you're having the same conversation

Another tip for having better conversations is getting clear on exactly what kind of conversation you're having.

Duhigg recalls a time when he'd return home from a tough day at work and complain to his wife about his difficult boss.

His wife would offer practical advice like: "Why don't you take your boss out to lunch and get to know each other better?"

But Duhigg would just become more upset.

"I'd say, 'You're supposed to have my side on this, I want you to be outraged on my behalf.' And then she would get upset because I was acting so irrationally."

He presented this dilemma to some of the experts he interviewed for his book, Supercommunicators: How to Unlock the Secret Language of Connection.

"They said we tend to think of a discussion as being about one thing; you know, that plan for our vacation or what to do about our taxes.

"But actually, every conversation is multiple kinds of conversations."

There are practical ones, in which we have to make decisions or solve problems, and emotional ones, which might be more about just listening and empathising.

Duhigg realised he was coming home and having an emotional conversation, while his wife was having a practical one. Both are valid, but because the two weren't having the same kind of conversation, they couldn't hear each other.

"That's what need[ed] to change," he says.

Making communication changes and building conversation skills can have a remarkable impact on the way we interact with each other, Duhigg says.

"If I just listened like literally half an inch more deeply, I'm going to hear you telling me things about yourself that are amazing."