Life, death and a sleepy lizard: One researcher's remarkable work on a monogamous blue-tongue

Updated

One man was behind almost everything we know about sleepy lizards.

We know that sleepy lizards live for 50 years in the wild; that they display an incredible system of perennial monogamy, coming together in an elaborate annual, slow-motion dance.

We know they have long-term friends and foes and a complex social network.

And we know that they grieve.

We know all this because of a 35-year study led by Flinders University's Michael Bull at a place called Bundey Bore in South Australia.

"It's a big slow-moving skink," Professor Bull told me when we spoke last year.

"It's around about 30cm long, it weighs up to nearly a kilogram and it's got armoured scales which give it protection."

Also known as the shingleback, the stumpy tail, the pinecone lizard and the bob-tail goanna, Tiliqua rugosa is found across southern Australia.

"When you come across it, its main form of defence is to open up its mouth and hiss at you with a big, blue tongue. It looks quite imposing," said Professor Bull.

Bundey Bore Station is in the rain shadow of the Mount Lofty Ranges. You drive off an escarpment at Burra onto flat, dry land, which continues that way until you reach the Murray River.

The flats are home to many thousands of sleepy lizards, which are omnivorous. However, their puny legs mean they mostly eat foliage, especially flowers.

It's not uncommon to see a sleepy lizard with its mouth stuffed with flowers petals sticking to its lips.

As an honours student, Professor Bull's focus was parasites, specifically the ticks that suck sleepy lizards' blood.

But as his work continued, he became more and more endeared to the ticks' slow moving hosts.

Then he noticed something strange.

"During the springtime we have this incredible situation where the male will follow closely after the female for many days and up to eight weeks before they get to mate," said Professor Bull.

"The male follows the female within a few centimetres; it's like a little train.

"When I first saw this I was a young biologist and thought that since the sleepy lizard was one of the more common species in southern Australia, certainly that everyone would've seen this and would know about it."

When Professor Bull returned the next year, he found the same two lizards together.

"I looked in the literature, and found that nobody had reported it in any other lizard anywhere in the world," he said.

"So this really common species was showing this completely unique behaviour."

The studies led by Professor Bull completely overturned the previous understanding of reptiles as scaly, unsociable recluses.

His investigations revealed complex social networks between lizards, which visit and share overnight safe zones with each other, and can navigate well outside of their own small territories, making their way back home like a very slow homing pigeon.

He even observed grieving behaviour in the reptiles when a member of a pair is killed.

"In one case a female got her head caught in some chicken wire," he said.

She pushed her head though and couldn't pull it back out again. The male hung around for two days.

"He'd come and revisit her every half hour or so: he'd be nudging her, he'd be tongue flicking, it was as if he was saying, 'What's wrong? Let's carry on like we were before.'

"Everyone tells us that lizards don't grieve, because they're not humans. But, they're doing what we think is analogous to grief.

"It certainly demonstrates the strength of the pair bond: that it persists beyond death."

The sleepy lizard project grew each year, attracting multiple grad students and collaborators from around the world.

Professor Bull climbed the academic ladder at Flinders University and took on more responsibility, including as editor of the journal Austral Ecology, and Dale Burzacott took over as the sleepy lizard study's project manager.

He looked after much of the logistics, field organisation as well as data entry — a huge job on a site that became more and more complex with each passing year.

Mr Burzacott had an intense enthusiasm for the lizard work: he was unstoppable.

Starting in 1983, he captured and re-captured 34,044 sleepy lizards at the Bundey Bore site.

This incredible investment of time is what made the pair's research so remarkable. A three-year study would not be able to prove that pair monogamy lasts for a whole lizard life span. Professor Bull's study site could, and did.

"We've been doing this study for 35 years now and there are still some lizards that we caught as adults when we started that are still going," said Professor Bull.

As time moved forward, new technology was introduced: GPS loggers were added and complex genetic analysis began on the ticks that the lizards transported within their territories.

Ever more complex questions were being asked, and the data was providing answers.

"These long-term sites are really essential part of Australia's environmental infrastructure," says David Lindenmayer, a professor of ecology at the Australian National University who has several long-term ecological monitoring sites of his own.

"The national environmental infrastructure tells us about how the environment is performing and how it is changing in relation to other changes — it might be land use, climate change or it might be other things that we don't even understand yet.

"And the only way you can understand these things is through very long-term research and monitoring; through doing repeated measurements year after year after year.

"What we often see is that some of these very important, very long-term studies are maintained by a champion for the project. That's one of the strengths — that you've got someone with the drive and the passion to make these projects happen — but it's also one of the weaknesses.

"We've seen from many examples around the world that when the champion of the project retires, dies, moves on: those projects can collapse."

Death of a researcher

Professor Michael Bull completed his last field visit for 2016.

A lizard hissed at him with its blue tongue and its mouth full of flowers and he drove the highway back to Adelaide from Burra. Another field season was wrapping up.

Then, one morning after his normal exercise, Professor Bull had a heart attack in the gym change room and died. He was 69.

The immediate responsibility for informing everyone involved in the study fell to Associate Professor Mike Gardner, a former student and Professor Bull's presumed successor, though no real planning for a takeover had been undertaken.

"When I rang Dale he was in the field at Bundey Bore," Professor Gardner said.

"I rang him up and I said what'd happened to Mike, and that he'd passed away. He said 'thank you very much' and hung up on me quite abruptly.

"Then five minutes later he rang me back and said: 'Sorry about that, I just had a moment.'"

Mr Burzacott had worked with Professor Bull for 35 years in an incredibly long and fruitful research relationship.

Mr Burzacott had all the hands-on experience, and though there was still no official succession planning in place, he attempted to impart what he knew to Professor Gardner.

"I now see that Dale was trying hard to tell me what was happening in the field. He kept shooting information at me and I kept putting him off," said Professor Gardner.

"Everything's great in hindsight."

Then, just a few months later, at 3:00am on a Tuesday morning, Mr Burzacott had a brain aneurysm.

He was taken to hospital brain dead, and was pronounced deceased.

"Both of these people passed away within a few months of each other with a body of work that is substantial," Professor Gardner said.

"I think this data set is bigger than both of them. It's something that needs to be continued not because of them, but for the rest of science really."

The death of the study's academic leader and the logistical organiser within months of each other was a tragedy for ecological monitoring in Australia.

Academics are highly specialised, no-one is like another, no filing system is quite the same, no post-graduate supervision approach is equal, no thinking is identical, and they often approach their work in such idiosyncratic ways.

It isn't entirely obvious how the 35 years of the study was organised in practical terms.

But Professor Gardner has pulled together a group of Professor Bull's former graduate students, now academics scattered the world over, and field assistants from years gone by to help him undertake the first season of sleepy lizard studies without Professor Bull or Mr Burzacott out in the scrub.

But despite the goodwill, the future of the project is unclear and funding is uncertain. Professor Gardner estimates there is just a 20 per cent chance of gaining funding in the Australian Research Council grant system this year.

"I'm definitely committed to doing this," said Professor Gardner.

"It's vital to the ecological community in Australia that we continue this, because long-term data sets are extremely rare and this one is probably the longest-running lizard survey in the southern hemisphere, if not the world."

Michael Bull and Dale Burzacott are missed by their friends, colleagues and families.

And after their work proved conclusively that sleepy lizards had long-term relationships, internal maps of their world, annual rituals and rhythms, maybe they will also be missed by several hundred reptiles who live in the scrub at Bundey Bore.

UPDATE: Flinders University has started raising funds to continue the sleepy lizard project. More information is available on their website.

Topics: ecology, environment-education, environment, academic-research, burra-5417, sa

First posted