Australian Megafauna

LINKS:
Extinct and Enormous: The massive marsupials of Australia: https://video.link/w/bIGsd
When Giant Lizards Ruled Australia – Megalania: https://video.link/w/LHGsd

EPISODE TRANSCRIPT

Massive marsupials taller than your teacher… lizards longer than your car… birds with the thighs of a rugby player… This is your Squiz Kids Shortcut to Australian megafauna—the podcast where we dive into the who, what, when, where, why and how of the big news stories. I’m Amanda Bower.

And I’m Bryce Corbett.

Lately we’ve been hearing in the news about how collisions with ships are causing a decline in marine megafauna populations. Which had us here at Squiz Kids confused… because aren’t megafauna extinct like the dinosaurs?

Today, we’ll take you through WHAT megafauna are; HOW mega we’re talking, exactly… and WHY they went extinct.

Listen carefully – there’s a Squiz at the end!

WHAT
Well Bryce, I’m sure your primary school teacher taught you that whenever you find an unusual word, it helps to look at parts of the word and see if they’re familiar. Let’s do that with megafauna. What does “mega” make you think of?

Well, I’ve heard the term “megastar”, and that means someone who’s hugely famous… and people talk about “megamansions” when they mean a really, really big house. So I’m thinking that mega means big, or huge.

Precisely! And how about “fauna”?

Hmm… I’ve heard the phrase “flora and fauna” a lot, when scientists talk about the plants and animals living in an ecosystem. And “flora” sounds like “flower”, so I’m thinking that’s probably the plants. I’d predict that fauna means animals.

You had a great primary school teacher! Yep, megafauna simply means big animals. To be quite precise, it means animals with a mass over 40kg. But the reason we were so confused about those stories of whales hitting ships is that when most people talk about megafauna, they’re referring to a particular group of very large, now-extinct animals that evolved after the dinosaurs died out 65 million years ago.

I’m guessing that once the dinosaurs were gone, there were no large land animals on earth.

Yeah, which meant that other animals could evolve – meaning slowly change to the environment around them – and get bigger to fill that gap. Over millions of years, many of the surviving mammals, birds and reptiles got a lot bigger. These megafauna were at their largest and most widespread in what is known as the Quaternary Period (pron: k-WHAT-uh-neri. That started about 2.5 million years ago, and we’re still in it! Because when you talk about the life of the earth, (FX) 2.5 million years is just the blink of an eye!

Amazing. Okay, so in the last 2.5 million years… just HOW big did these megafauna get?

HOWWell in this podcast we’re focusing on the megafauna unique to Australia during the Quaternary period. And I reckon my favourite is Diprotodon (pron: dye-PRO-tuh-don)… the largest marsupial known to have existed on Earth. Imagine a wombat, and then make it absolutely MASSIVE, with longer legs. It might be worth pulling out a tape measure and marking out 3.8 metres on the floor. That’s how LONG diprotodon was from head to tail. (Bryce react) Now measure 1.7 metres up from the ground… that was Diprotodon’s shoulder height. I’m 1.75 metres tall, and if I imagine coming across a massive hairy bear-like creature, and my head only came up to its shoulder… wow…

If you did go back in time, would it have wanted to eat you? 

Thankfully, no! Experts can tell from Diprotodon fossils that it had the teeth of a herbivore… meaning it only ate plants. In fact, they think Diprotodon ate up to 150kg of vegetation every day!

I suppose if you weigh 2,800kg, you do need quite a bit of food each day…

For sure! There were also mega-ancestors of today’s kangaroos and wallabies, but megafauna is more than just marsupials and mammals! It also includes birds, and Australia is known for its “mihirungs” (pron: MI-hee-rung)- large, flightless birds. Genyornis (pron: jen-EE-or-nis) is the most recent one to have walked on this land, and if you imagine an emu that’s over 2 metres tall with extraordinarily thick legs, you’ve got a pretty good picture. They’ve found Genyornis egg fragments in sand dunes, and those eggs were almost twice the size of emu eggs… imagine an egg that weighs 1.6 kilos!

A chicken’s egg weighs about 50 grams, so… pause if you want to do the maths yourself… that’s the equivalent of 32 chicken eggs! (FX)

Then there are the mega-reptiles… and Australia had the biggest land lizard known to have existed in the world, the megalania (pron: mega-LANE-ia). Remember when we measured out 3.8 metres? Well, this gigantic monitor lizard could have gotten up to 7 metres long, and weighed as much as 1,900 kg!

That is a LOT of lizard!

Scientists haven’t found a complete set of remains of megalania – it’s thought to have gone extinct 50,000 years ago, so there’s still a fair bit of debate about how big they really got… it’s tricky studying things that no longer exist!

And of course that’s the burning question… WHY did all these massive animals go extinct?

WHY
Megafauna came into existence during the last Ice Age, and when the world started to thaw out, that’s when they went extinct. Australia’s climate changed from cold and dry to warm and dry, and that meant that inland lakes were dry for months at a time. Megafauna were just too big, and couldn’t get enough food and water top survive from their new environment. Some did move to a narrow area in eastern Australia, where there was permanent water. Our friend diprotodon is thought to have survived on the Liverpool Plains of New South Wales up until about 7000 years ago.

So were the remaining ones hunted to death by humans?

You might think so… the best preserved skeleton of a Diprotodon, at the Australian Museum in Sydney, has a small, square hole on one rib that experts say could be a spear hole.

That would have fed a LOT of people, if you successfully speared a 2,800kg animal!

Absolutely! But First Nations people have been in Australia for 60 000 years, so megafauna must have co-existed, meaning lived together, with humans for at least 30 000 years. We also know that all over the world, indigenous people hunted in a sustainable manner – they knew they had to keep the food supply coming, but also, there were social and spiritual reasons to take care of animals and the earth.

I have to say, I’m a bit sad that Australian megafauna went extinct… I’d LOVE to see them in real life.

Well Bryce, all is not lost… we still have megafauna! Remember it technically means over 40kg, so we have smaller animals that evolved from those early Quaternary period megafauna: red kangaroos, emus, saltwater crocodiles…  and our oceans are home to the biggest living marine megafauna in the world: blue whales, whale sharks, leatherback turtles…

Megafauna for the win!

The S’Quiz
This is the part of the podcast where you get to test how well you’ve been listening…
1. What did the massive marsupial Diprotodon like to eat?
2. One egg of the massive emu-like Genyornis weighed as much as how many chicken eggs?
3. What’s the main reason most megafauna went extinct?