Daniel wondered about the evolution of emus and other things

Daniel had some wonders about emus. A simple answer wouldn't have allowed me to share the information I had…

Hi Ross! I liked how you wrote each of us a comment. Thank you for sending us the animal cards because we got more wonders. What did the emus evolve from and what is the tallest bird? I wonder how the real name of the emu is pronounced. How can you tell the difference between a male emu and a female emu? If you didn’t send us the cards, I wouldn’t know that emus swim! Which continent is Polynesia on? We are so lucky that we blog with you, Ross!

Daniel, what wonderful wonders!

As can sometimes happen, a comment can lead to a post so let's see if I can answer your questions. I like challenges. 🙂

Let's work backwards through your questions.

1. Which continent is Polynesia on?

Polynesia isn't a continent. It is a collection of over 1000 islands in the Pacific Ocean. It includes Hawaii in the north, Rapa Nui (Easter Island) in the east, Tonga in the west and New Zealand in the south-west. The traditional people of the islands are known as Polynesian. Having heard the Maoris of New Zealand speaking their language, I have also visited Hawaii. Despite the two sets of islands being so far apart, I was able to recognise words similar to each area.  Polynesians share similarities in culture and language.

As well as Polynesia, there are two other major Pacific island groups, Micronesia and Melanesia. Melanesia includes New Guinea to  the north of Australia. Australia isn't part of these groups as it is both the world's largest island and smallest continent. The many cultures of the traditional people of Australia are very different to Micronesians, Melanesians and Polynesians.

Schools and students have permission to use this graphic for non-commercial, educational purposes.

Schools and students have permission to use this graphic for non-commercial, educational purposes.

A Maori in traditional clothing.

2. What is the tallest bird?

The heaviest and tallest living birds are ostriches, native to Africa. They can weigh over 156kg and the males can be as tall as 2.8m. Next on the list are southern cassowaries found in northern Australia. Emus come along in 3rd place. The northern cassowary found in New Guinea comes in fourth. I have seen emus in the wild. I have only seen cassowaries and ostriches in zoos. Here is a Wikipedia link…

List of Largest Birds

When the Maoris first arrived in New Zealand (aka Aotearoa), they found a very large flightless native bird known as the moa. Look at the photo below of a reconstruction of the moa based on evidence from bones and fossils...

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Schools and students have permission to use this graphic for non-commercial, educational purposes.

I photographed this moa in New Zealand's Auckland Museum. There were nine species of moas, this being one of the largest two. They could reach about 3.6m in height and weigh about 230kg.With the emus reaching up to only about 2m, the largest moas would have towered over them.

But these weren’t the largest known birds to have ever lived. Does a bird thought to be more than 3m tall and weighing around 400kg sound big? Here a link to an extinct giant bird…     Elephant Bird

3.How can you tell the difference between male and female emus?

emu (eem-you)

Schools and students have permission to use this graphic for non-commercial, educational purposes. This graphic should not be used without written permission from me.

Schools and students have permission to use this graphic for non-commercial, educational purposes.
This graphic should not be used without written permission from me.

The most important answer to this question is the birds can but let's see what I can find to help us. By looking at the photo above, I can't tell the difference between the male and female emus. They look very alike but it seems they can sound different. Males can grunt a little like a pig and, if they're caring for chicks, can whistle to their chicks whereas females make a more booming sound.

When I look at emus, I try to imagine them featherless with teeth in their beaks. When I do this, I imagine something like a dinosaur. Look at the photo of a dinosaur skeleton I photographed when at a museum in London. It has a long tail and clawed upper arms whereas  emus have a short tail and stumpy wings we don't notice because of their feathers but there are similarities such as in their feet and the way they moved. I suspect the dinosaur was a fast runner and I know emus can run at up to 50 kilometres per hour as I have been driving a car and slowed to see how fast nearby emus were running.

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Schools and students have permission to use this graphic for non-commercial, educational purposes.

 Of course, looking something alike doesn't mean they are alike. There can be similarities between very different animals simply because they need to do similar things so let's look at some ideas on the evolution of birds.

4. Where did emus evolve from?

The Evolution of Birds

For a long time people thought all of the dinosaurs died out with the great extinction caused by a large meteorite hitting Earth but we now believe this wasn’t completely so. We know the large dinosaurs couldn't survive the changes in the Earth but early mammals survived because they were small and fur covered. Fossils have shown this but what about the small dinosaurs?

I have seen information on two main types of dinosaurs...

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Schools and students have permission to use this graphic for non-commercial, educational purposes.

No, I didn't take the dinosaur photo when I was young. In 1989, I visited a dinosaur display. 🙂

the sauropods (lizard-footed) including the largest dinosaurs (one is pictured above)…   Sauropods

and the ornithopods (bird-footed)...    Ornithopods

By their names, you might think we would be looking at ornithopods but it’s the sauropods I find most interesting, as it seems these dinosaurs include the ancestors of birds.

A type of sauropod dinosaur are the therapods (beast-footed)...     Therapods

Could some dinosaurs fly?

 Look at the photos I had taken when a "DInosaurs of China" collection visited Sydney in 1983...

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Schools and students have permission to use this graphic for non-commercial, educational purposes.

This high quality fossil from China shows a winged reptile and the photo below shows a reconstruction of how they may have looked. These fliers weren't dinosaurs although many think of them as being dinosaurs. They were not the ancestors of birds.

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Schools and students have permission to use this graphic for non-commercial, educational purposes.

We had no evidence dinosaurs had feathers until a very fine fossil was found in 1861, an archaeopteryx (are-key-op-ter-ix). Look closely at the photo below and you will see the fossil below is so fine you can see feathers yet it appears to have claws on its wings. This was not the fossil of a flying reptile. If the feathers hadn't been present, it would most likely to have been thought to be a small sauropod dinosaur. After the fossil was discovered, we could see a link between the dinosaurs and birds.

Schools and students have permission to use this graphic for non-commercial, educational purposes.

Schools and students have permission to use this graphic for non-commercial, educational purposes.

In  the photo below, you will see how the archaeopteryx might have looked. Fossils don't preserve colour so the colours are only guesses but sometimes ancient feathers have been discovered in amber and can show colour. Because feathers trapped in amber are rare, scientists can't test them without destroying them to find out more but they have been found to be very old feathers.

Schools and students have permission to use this graphic for non-commercial, educational purposes.

Schools and students have permission to use this graphic for non-commercial, educational purposes.

Since the discovery of the archaeopteryx, more examples of fossils appearing to have feathers have been found...

Feathered dinosaurs

Scroll down the link and you will see a diagram known as a cladogram. The diagram shows a clade. Clades show an ancestor and all of its descendants sort of like a family tree humans use to show their family. Notice the ancient ancestor starts with therapods and leads to birds?

All dinosaurs didn’t become extinct, some evolved into the birds we see today.

Do any modern birds have claws?

I once wondered if any modern birds had clawed wings and the answer was no until I read about the hoatzin of South America. The hoatzin is also known as the "stinkbird" which gives us the idea it is a little smelly.

What interested me was its chicks. The chicks have two claws on each wing to help them climb around the trees where they live but they are true birds and not left over from the dinosaur days. The young lose the claws as they become adults. Below is a photo of a hoatzin chick I found on Wikimedia Commons where it is listed as in the public domain.

This photo was sourced through WIkimedia Commons where it is listed as in the public domain.

This photo was sourced through WIkimedia Commons where it is listed as in the public domain.

The Evolution of the Emu

Science tends to classify birds into orders and into further groups within orders. For the emu, it is grouped with other ratites, or flightless birds including the ostrich, cassowary and New Zealand's moa and kiwi. In the link below, you will see another cladogram, this time of birds. The ratites come off very early on and are separate from all other birds so you could say they are closer to the first birds to have evolved.

Classification of Modern Bird Orders 

One last photo, this time a close up look at the emu's legs...

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Schools and students have permission to use this graphic for non-commercial, educational purposes.

Emus are modern birds and not dinosaurs but, when I watch them walk, I can imagine them being dinosaurs striding or running across the land perhaps being chased by a carnivorous dinosaur. What do you think?

One thought on “Daniel wondered about the evolution of emus and other things

  1. The Battalion Bloggers

    Hi Ross!

    Sorry – it’s taken us a while to reply to the amazing comment you left for Daniel as well! Here are our reflections on that awesome post about the evolution of birds:

    “Hi Ross! It’s amazing that you got that close to an emu! Did you use a ZOOM lens? We love all the links that you put on your posts. Guess what? Now we are interested in emus and dinosaurs because of your comment! Why do you like sauropods so much? I’m surprised an emu didn’t jump in your car when you were driving, when you were testing how fast it was going! Ross, what is the biggest emu you have seen? Where have you usually seen emus?” ~Ethan, Isaac & Alex

    “Thank you SO much, Ross, for that awesome comment to Daniel. It was cool how the hoatzin chicks climb the trees! How fast was the emu that was running beside your car? I never knew dinosaurs had feathers! We’ve been looking at an eagle cam and it’s skeleton looked like a dinosaur! The winged dinosaurs give me the creeps. I can’t believe you got THAT close to an EMU! Thank you, again, Ross … you are thoughtful!” ~Kale

    “Thank you so much, Ross! Mrs. Renton has a book and here are some of the facts I’ve found:
    – the biggest egg is laid by the ostrich! (170 by 130 mm and it weighs 1 400 grams!)
    – the ostrich family contains the biggest flightless birds and emus, cassowaries, maos and elephant birds, (which are extinct).
    – an ostrich can run 60 kph or more!
    I wouldn’t have known the facts if you didn’t follow our blog! Thank you!” ~Melvin

    “Hi Ross! Wow! The ostrich is humungous! It’s amazing you know all about these awesome animals! We never knew that polynesia was made up of 1000 little islands! That’s a LOT … and I mean a LOT! Have you ever seen an emu on your street? Have you ever felt an emu … and if you did … what does it feel like? Thanks, again, Ross, for always extending our learning!” ~Amy, Catherine and Noam

    “Hi Ross! It’s really amazing that the moa can reach 3.6 m in height and weigh 230 kg and that there is a living bird with claws! It is called the hoatzin! Another name for it is “stinkbird”! What was the most spectacular thing you saw in the Aukland museum in New Zealand? It’s cool that you could take a photo of the emu’s legs SO close! Thank you for the post, Ross!” ~Martin and Zyne

    “Hi Ross! Thank you for an awesome extended comment! We loved EVERYTHING! Our group was wondering what the adult stinkbird looks like! We never knew that stinkbirds were also called hoatzins! We also wonder how you got so close to the emu! A grade six teacher in our school is about the size of an ostrich because he is about 2 meters tall! We wonder what a daddy emu is called? Our group wonders how many types of emus there are on earth? When you were at the dinosaur display what was the best thing there? Our class has been looking at eagle cams. It’s so cool … and we saw the eggs!” ~Jenna, Hilary and Claire

    “Hello Ross! Thank you for sending us an amazing comment on our blog. The information you said about emus made me excited. The picture that was my favourite was the emu feet. Ross, you are a genius to me because you send interesting facts and information! I hope that there is still time for you to send us some more facts, Ross!” ~Lane

    “Ross, thank you for writing back on the blog! In China they only put the boys on one family tree and the girls are on a different on! Weird! How close have you ever been to an emu? What was the most best artifact you saw in the London Museum? Are eagles related to dinosaurs because when we looked at a skeleton of of one it looked like a dinosaur! What is your favourite bird?” ~Peng Peng and Daniel

    “Hi Ross! Thanks for the awesome facts! We never knew about those emu facts! How do you know so much about emus? If you never told us about emus we would not be able to know so much about emus! Wow! You did a LOT of research! We are so lucky that you researched for us! You really did not have to do that for us! Ross, what do you like about emus? Once again, thank you so much!” ~Aya, Hannnah and Kelly

    🙂

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