Cristy Burne


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Celebrating sawfish on Shark Awareness Day

Did you know sawfish are related to sharks?

When I took on this story for CSIRO’s Double Helix magazine I didn’t know much about sawfish at all.

Now I know they’re a type of ray. I know they use their saws to detect the heartbeats of their prey, and also to stun fish and defend against predators. And I know they used to live around the world, but are now endangered. How cool is it to be a science writer and learn all these things as part of my job!!!

Double Helix Sawfish.JPGFishing up a huge surprise

It started out as just another fishing trip.

Lisa Smiler was using a handline in Wattie Creek, 900 kilometres south-west of Darwin, in the Northern Territory, when she felt that unmistakeable feeling: a bite on the end of her line!

“I thought it was a barramundi, or a catfish, or something,” Lisa says. Whatever it was, it was big.

“I was pulling the line, then my sister helped pull the line, and her partner pulled the line, all the way up to the edge of the river,” Lisa describes. “All of a sudden, my sister pulled up the nose part, and I said, ‘Oh no, I don’t want this fish, it’s freaky.’”

At 2.7 metres long, the fish weighed more than Lisa did. When she posted its picture on social media, Lisa set the scientific world alight.

Record-breaking fish?

According to Western science, Lisa’s sawfish is the first ever observed swimming so far inland—nearly 500 kilometres from the ocean!

But Indigenous knowledge says differently. Local rock art of a sawfish, or kunpulu, suggests Lisa’s ancestors had seen the fish already.

Ursula Chubb, a Gurindji ranger, monitors the rock art site. “When we go out on country trips with Elders, they talk about it, and I listen to them telling us stories,” she says. “It’s a very important fish from long ago, when our ancestors were living in this country.”

Lisa says she never dreamed she’d see a live kunpulu. “I’d just heard about the sawfish in the rock painting … I wasn’t thinking I would catch one.”

Tracking language

Kunpulu’ means ‘sawfish’ in Gurindji, and in other Indigenous languages too, even those spoken hundreds of kilometres from Gurindji country.

Dr Felicity Meakins has studied Indigenous languages for over 20 years. She says different words tell their own stories, and she uses these stories to learn about changes over time.

“You can use different languages to trace the path of the fish,” says Felicity.

“I would guess at some point this fish has appeared, and people have said, ‘This is a stranger in our country. What’s this?’ And they’ve asked more northern people…and that’s how that word kunpulu has been passed along.”

Solving the mystery

We don’t know when Gurindji people first saw sawfish, but with ochre samples from the rock art, we hope to be able to solve the mystery. Scientists have also taken DNA samples from Lisa’s sawfish, to help work out how many sawfish are in the river.

“We’re using Indigenous ecological knowledge and western knowledge to build up a picture of what’s happened with the sawfish,” Felicity says.

Endangered wonders

Sawfish once lived around the world but are now endangered. Baby sawfish are born in the ocean, at the mouth of rivers like the Northern Territory’s Victoria River or Western Australia’s Fitzroy River.

The pups swim upstream, spending years growing in the river before swimming out to the ocean. Adults can reach up to seven metres long.

 

My article was first published in CSIRO’s Double Helix magazine.


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How to tickle a rat: serious news on International Joke Day

giggling rats Helix.JPGIt’s International Joke Day, but let’s get serious. Evidence suggests a good laugh is great for our health. But what if you just don’t feel funny? Can tickling help?

That’s where research comes in. Dr Shimpei Ishiyama is studying tickling and laughter in rats. It turns out, anyone can learn to tickle a rat, he says.

“It is very easy…though there are some techniques, such as flipping them and tickling the belly, which you may need to practice a bit.”

Shimpei is studying the way rats’ brains react to a good tickling. He hopes to learn more about how our own brains work.

“Our results suggest that ticklishness has been conserved through evolution, and is related to playfulness. We speculate ticklishness is perhaps a brain’s trick to make us play with others, and have fun,” he says.

Ready, set, tickle

Shimpei and his team of ticklers have even noticed differences in rat personalities. Shy rats tend to laugh less, while playful rats laugh more.

Shimpei loved being tickled as a kid, but now he hates it. “It is also the same for rats. Young rats enjoy being tickled, while adult rats are annoyed,” he says.

meme-ratTop tickler’s tip:

Before you attempt to tickle your rat, take a deep breath. It’s important that you’re feeling relaxed and friendly.

“Rats…can sense the stress hormone in sweat on my palm, which could potentially make them nervous,” says Shimpei.

Is your rat missing its sense of humour?

Worried that your rats are too serious? Don’t worry. It’s normal to feel this way. And it could be your rats are having a super time, you just don’t realise.

Rats laugh at ultrasonic frequencies, so the human ear cannot hear their giggles.

I originally wrote this article for CSIRO’s Double Helix magazine 🙂 


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How to spot (and help) platypuses 

DSC_0020I’m lucky enough to be heading to the Whitsundays Voices Festival a couple of weeks early. Why? For some sun and beaches, but also some forests and hiking…

I’m also hoping to see a small, furry critter I’ve adored from afar but never actually laid eyes on:

The platypus.

On a scale of one to weird…

On a scale of one to weird, platypuses score super-high. They’re venomous, lay eggs, make milk, breathe air and live in fresh water. How cool is that!?!?!

“It doesn’t get much weirder,” says Josh Griffiths, a senior ecologist with 10+ years’ experience working with platypuses.

“They’re the most unusual creature on the planet. There’s still so much we don’t know about them, so any time I go out or do research, I’m going to see something new.”

DSC_0306.jpgWhat do we already know about platypuses?

Well, we know platypuses are amazing.

Bill: Their super-sensitive bill can detect underwater electrical pulses made by tasty beetles, insect larvae and yabbies. This means platypuses hunt with their eyes, ears and nostrils closed.

Limbs: Their short limbs are webbed (great for paddling) and clawed (great for digging).

Spur: Males have venomous spurs on their ankles. “The venom causes excruciating pain and massive swelling in humans,” says Josh. Platypus venom is so odd, we’re hoping it can be used to treat diabetes.

Coat: Their thick waterproof fur is perfect for staying warm and dry.

Tail: Flat and wide like a paddle, their tail is great for swimming. It’s also filled with fat, for energy reserves.

Size:  1–3 kilograms. “Like a small rabbit,” says Josh, “but they’re a very strange shape, because they’re long and streamlined.” Think 40–50 cm from tip of tail to tip of bill.

Eggs: The female lays her eggs in a 25-30-metre-long burrow that she’s dug into the riverbank. “It’s quite an effort for a one-kilogram animal,” says Josh. “The eggs around about the size of a 5-cent piece when they’re laid.” After just ten days, the eggs hatch.

Jellybean babies: “When platypus hatch, they’re the size of a little pink jellybean,” says Josh. “They’re basically a mouth, with not much else. Mum stays with them almost constantly for the first few weeks.” During this time, she feeds her bean babies with milk.

Milk: A CSIRO team led by Janet Newman has found a curly protein in platypus milk is great at killing bacteria. “Platypus are such weird animals that it would make sense for them to have weird biochemistry,” says Janet.

Where to see platypuses

Platypuses live across eastern and southern Australia. They’re mostly nocturnal, live alone, and are super-shy. “We don’t see them easily, so we don’t know whether they’re disappearing or not,” says Josh.

However, fingers crossed, they’re relatively easy to spot in the Eungella National Park, which is where I’ll be heading before the Whitsundays Voices Festival. Wish me luck!

Join the platypus party

Next time you go platypus-spotting, be a citizen scientist and record your success (or failure) on platypusSPOT.

“You can see where other people have seen platypus and try your luck in those hot spots,” says Josh. Even better, your information helps us learn more about where platypus live.

IMG_1723-2.jpg

Platypus can drown in yabby traps

What you can do to help platypuses today

There are two big ways we can all help platypuses:

  • Save water. “Every time we take a shower or turn on the tap, we’re using water from a platypus’ home,” says Josh.
  • Pick up litter: “It’s easy for a platypus to get tangled rubber bands or hair ties or bits of string,” says Josh. Platypuses also drown in yabby traps.

Injured platypus? Who you gunna call?

If you find an injured or sick platypus, don’t pick it up. “You could get put in hospital for your trouble,” says Josh. Platypus venom isn’t fun! Instead, call your local wildlife rescue operation.

Did you know?

Platypuses are one of only five living species of egg-laying mammals, called monotremes. The other four are all echidna species. Monotremes only live in Australia and New Guinea.

This post is adapted from an article written by me that first appeared in CSIRO’s Double Helix magazine. (c) CSIRO


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Could Harry Potter’s Invisibility Cloak really make someone invisible?

I’ve been thinking lots of good science thoughts this week because I’m dreaming up a new and exciting project.

Science is pretty cool, and science for kids is even cooler. Many of you know I used to perform kids science shows as part of the Shell Questacon Science Circus and for Science on the Move. I’m also a past editor of Australia’s Scientriffic magazine, now Double Helix.

(If you want awesome science activities and news delivered to your inbox every week for free, subscribe to the FREE Science by Email…it’s brilliant).

But, back to the title of this post:

Could Harry Potter’s Invisibility Cloak really make someone invisible?

And the answer is…

Maybe!

If your eyes are open and the lights are on, you can see most things. Objects are visible because they reflect or bend the light that hits them.  If you can see something, it’s because light is bouncing from that something into your eyes.  Some things — like air or water or glass — are transparent or translucent, so instead of reflecting all the light that hits them, some of that light can shine right through them. Transparent things are harder to spot, but there is one giveaway: light usually bends as it shines through an object.

The speed of light in a particular material is constant.  However, when light moves between two different materials, it usually changes speed.  This change in speed causes the light to bend, and our eyes can detect the change in its direction.

For example, when light moves from the air into a raindrop and back out again, the light changes speed, which causes the light to bend.  Our eyes can see this bend in the light, which is why we can see raindrops falling in the sky.

Each material bends light by a particular amount.  We call this amount the refractive index of that material.  If the refractive index of rain was exactly the same as the refractive index of air, light wouldn’t bend as it went through a raindrop falling in the sky.  And if the light didn’t bend, our eyes couldn’t see the raindrops falling at all – they would be invisible!

So…

If the refractive index of Harry’s cloak was exactly the same as the refractive index of the air in a room, the cloak would be invisible in that room.

But…

Even if Harry’s cloak was invisible, we would still be able to see Harry underneath it!  Harry’s body would have a different refractive index to the air, and to his cloak, which means he would still be visible behind his cloak in the same way that you are still visible behind a glass window.  For the cloak to make Harry invisible, it would need to change the refractive index of Harry’s body to exactly match the refractive index of the air.

Impossible? Yes. But only in a world without magic 😉

Question to think about: Would Harry’s cloak still be invisible if you looked at it underwater?

And of course, an activity to try at home!

Matching refractive indices

This experiment demonstrates that if light passes through two media with equal refractive indices it will not bend nor reflect at the boundary.

  1. Put a small Pyrex bowl inside a larger Pyrex bowl.
  2. Pour Baby Oil into the small bowl till the oil overflows into the large bowl. The refractive index of Baby Oil is nearly equal to the refractive index of Pyrex glass. The small bowl should become practically invisible.
  3. If you have a glass eyedropper try putting it into the oil.  It will be easy to see because of the difference between the refractive indices of air and glass.
  4. Try sucking up the oil into the eyedropper.  The eyedropper should become almost invisible because the refractive index of the glass is nearly the same as that of the oil.  When light passes between the oil and the glass it is only bent a little, and the dropper appears invisible.

Note: If you don’t want to waste the baby oil, use the glass to pour it back into the bottle. Make sure you do this over the bowl so it doesn’t get everywhere.

This post is a revised version of my original article, first printed in The Helix magaazine.

Other posts you might enjoy:

Enma Daio, Datsue-ba, and one great reason to die with your clothes on

How to keep your New Year Resolution: Papier mache daruma dolls

Takeshita Demons: help us choose the cover art

8 cool myths about dogs, and why the inugami dog-god didn’t make it

Hiragana word search: Find the yokai demons and practise your Japanese