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Tommy Leung



Tommy Leung

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Of Pigs, Chimps, And Dinosaurs
[Brace yourself, this is a long read]
It seems like ever since mid-2013, not a month goes by without hearing about what I would call "PigChimpMan theory" of human evolution. This "theory" has been lurking around for a while in its own obscure corner of the internet, but it initially came to the attention of a wider online audience via PhysOrg back in July 2013. However, the idea was well and truly launched like a dysfunctional bottle rocket in November 2013 into the mainstream when it was publicised by that bastion of rigorous science journalism, the Daily Mail. Subsequently, it had spread like a pandemic swine flu across other media outlets.

(BTW, I'm not going to link to those pages directly and give them the hits, but if you wish to see them, they can easily be found via a quick Google search)

But we're not here to talk about that, as the ridiculousness of that theory has been thoroughly addressed by +PZ Myers
And it was also addressed on episode 420 of Skeptic's Guide to the Universe (

To say that the originator of the "PigChimpMan theory" has some odd and misguided notions about evolution would be an understatement and it is not on the basis of the "PigChimpMan theory" alone. No, lest you think we are talking about a one-trick wonder, fear not - he also has a website call Macroevolution Dot Net (once again, I'm not linking directly for reasons stated above). This is where he has published many other "theories", though admittedly most of them appear to simply be a variation on a very simple theme, namely "X did the nasty with Y and ended up with Z"

Okay, some #realtalk  here - cross species hybridisation does happen - for example, a mule is a hybrid between a donkey and a horse, and there are also hybrids between domestic cattle and American bisons, and even hybrids between false killer whales and dolphins.

He claims that such hybrids lend support for his "PigChimpMan (and other similar) theory". However such hybrids are often sterile and only occur between species which are closely related - often from the same genus. The "PigChimpMan theory of human origin" is based on a faulty, slippery slope assumption that since hybridisation between closely related species is possible, then species across entirely different orders can readily hybridise. Just because two closely related species can form hybrids does not mean animals from entirely different orders (or entirely different classes as you'll see below) can produce reproductively viable hybrids. Basically, just because there are mules running about doesn't mean that Manx cats came from a rabbit humping a cat.

Oh, I forgot to mention that didn't I? That the creator of Macroevolution Dot Net thinks that Manx cats are actually cat-rabbit hybrids? Just FYI. But cross-order hybridisation is nothing comparing with his proposed origin of the monotremes (platypus and echidnas) which involve birds hybridising with mammals. Yes. Your read that right. He thinks that the echidna exists because a hedgehog got it on with a kiwi. Don't take my word for it - go to his website and check it out for yourself.

But it doesn't end there (it never does), let me present his "They look kinda alike to me" theory of evolution. He has some very strange ideas about dinosaur evolution which I am sure scientists like +Michael Habib or +John Hutchinson or +Darren Naish or just about anyone else who have at least some interest in and background knowledge about dinosaurs would find, well, questionable to say the least. For example, did you know that according to Macroevolution Dot Net, pangolins evolved from stegosaurs?

His "theory" pretty much amount to "Pangolin looks kinda like a Stegosaurus. An anatomically inaccurate Stegosaurus from an old kids book about dinosaurs I came across. And if I ignore just about everything about both animals. Therefore, I think pangolins are actually descended from dinosaurs and Stegosaurus is a mammal" Go check it out for yourself - I seriously, seriously cannot make this stuff up even if I tried. He thinks that pangolin plates are homologous* with the plates of Stegosaurus and that the tail spikes on the thagomizer of the stegosaur tail actually belong on the feet and were homologous to the pangolin's claws.
*A homologous structure is a one which is found in different species that share a common ancestry; for example, our arms are different from the wings of a bat - both have been modification for different purposes in our respective lineages - but they share a common basic architecture from a common ancestor.

He also claims that:

"The modern giant armadillo is so similar to the ancient ankylosaurs that it is only reasonable to suppose it is descended from them."

According to his theory, thyreophoran dinosaurs are in fact mammals. Well, I guess by that logic, one can claim that it is only "reasonable" that dolphins are descendants of ichthyosaurs, right? Right? Well...when he is not busy trying to claim one group of reptiles are mammals, he is also trying to claim that one group of mammals are in fact reptiles. The mammals in question are the cetaceans - whales.
While he is not exactly claiming that dolphins are evolved, modern ichthyosaurs, he does think that whales had evolved from mosasaurs. The mosasaur were a group of extinct marine reptiles which are related to modern monitor lizards and snakes that lived during the late Cretaceous period ( and they are essentially a lineage of lizard-type reptiles that had adapted to the aquatic environment.

Despite extensive fossil AND molecular evidence for the actual evolutionary origin of whales, he still cite his "They look kinda alike to me" theory of whale evolution, while being unfamiliar with something call convergent evolution ( whereby divergent groups of organisms have independently evolve very similar forms as they lived in similar ecosystems/environment and were subjected to similar evolutionary selection pressures.

If you want to read up on the non-unhinged theory about evolution of whales, this Wikipedia article has a good collection of links and references you can look up and read at your leisure:

Oh, one more little thing - he also has this annoying habit of repeatedly following and unfollowing people on Twitter to try and get them to follow him back. +Steven Hamblin called him out on this, to which he claims that it was "an accident" (he has also deleted all his tweet correspondence with Steven), but others have mentioned that they have been subjected to the same "follow-unfollow" cycle from him.
I think I'm currently in the third or fourth "follow" cycle from him, though I suspect this post might terminate that altogether.

To lighten the mood a bit after this very long post/rant, I would like to propose a new genre of internet literature call "Macroevolution Dot Net Fan fiction" (I think I have just invented the worst kind of fan fiction). Here are some potential title to start off with, but feel free to make your own.

Loris = Monkey + Owl hybird
Ambulocetus = Otter + Crocodile hybrid
Sea cows = descendants of placodonts (

Then again, he is probably working on those very ideas right now...
Sharing for +ScienceSunday 
#sciencesunday   #pseudoscience   #evolution   #evolutionarybiology   #scienceeveryday   

Accompanying photo is "The Listener" (2013) by Patricia Piccinini. You can see the rest of her artwork here:
Photo was taken by Ars Electronica and used here under Creative Commons license (CC BY-NC-ND 2.0). Original here:
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Worth noting that the Skeptics Guide to the Universe chose the "man-chimp-pig" story as one of the worst science failures of 2013, alongside such luminaries as "vaccines make you gay" and "bigfoot DNA". Lots of angels singing in this choir:

Tommy Leung

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Heart Of The Matter
I have written a new Parasite of the Day blog post! And for the first post of 2016, I have written about the lifecycle of a fish blood fluke, specifically Cardicola orientalis. This parasite has a lifecycle which involves tuna and polychaete worms - so what does it do to its hosts? Follow the post below to find out more!

Tunas are one of the most graceful animals of the sea. These sleek and powerful predators spend their lives in motion, cruising the open seas for prey. But despite being such formidable fast movers, this does not make them im...
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Ichthyosaur Survival Strategy
Mawaru Penguindrum is an anime series which aired during 2011 and directed by Ikuhara Kunihiko. He is also known to have directed Revolutionary Girl Utena, and more recently Yurikuma Arashi. Ikuhara is well known for using a lot of visual symbolism in his series, and Penguindrum is arguably the most visually and thematically dense show that he has directed so far.
Penguindrum is one of my favourite anime series and accordingly, my "PalaeoAnime" tribute for it is also thematically and visually dense as the anime itself. This piece covers the theme of the End-Permian Mass Extinction Event, the adaptive radiation of early to mid-Triassic marine reptiles, the evolution of the ichthyosaurs, and of course, it wouldn't be a Penguindrum tribute if it didn't involved Survival Strategy!
Mawaru Penguindrum is an anime series which aired during 2011 and directed by Ikuhara Kunihiko. He is also known to have directed Revolutionary Girl Utena, and more recently Yurikuma Arashi. P...
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Tommy Leung

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Zombie Ants And Monster Girls
"Hey Tommy, that 'Disney Princesses Reimagined As' trend got pretty popular, how about you do something like that?"
"How about...Parasites reimagined as MONSTER GIRLS?!"
"I…I don't think anyone wants that…"
See also a related post here:

Alternative title: 
"I'm Not Popular, So I'll Draw Parasites As Monster Girls."
Apparently I wasn't quite done with Parasite Monster Girls. After I drew Luci the Zombie Snail Monster Girl my brain decided that drawing one monster girl featuring a mind-control parasit...
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Tommy Leung

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The Bone-House Wasp And The Vestibules Of Death
Earlier today I was on ABC New England recording a new episode of Creepy but Curious - a regular radio segment that I go on once a month to talk about weird and wonderful animals.
This time, I talked about the Bone-house wasp Deuteragenia ossarium - a tiny insect with a number of macabre habits. First off, it is one of 5000 known species of spider wasps. These insects hunt spiders not to eat them - but to turn them into living larders to feed their developing larvae. They inject a venom into the spider which immobilises (but not kill) it, then lays a single egg on it. When the egg hatches, the larva eats the spider alive.
But as if that isn't macabre enough, the bone-house wasp also has a habit of collecting dead ants. Why? Find out more by following the link below to listen to (or download) the recorded segment.

It's a creepy and curious world out there and this week we head straight into the world of what sounds like the worst horror movie of all time
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Glad there's a podcast. Time zones are a bugger.
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What Parasitised The Dinosaurs?
I've written an article for +The Conversation about dinosaur parasites. Recently, I wrote a post about various fossils of prehistoric parasites (, which in turn was based on my review paper on the topic ( which was recently published in the journal Biology Reviews. In this article, I specifically focused on the dinosaurs and the type of fossil evidence that we have for their parasites - this includes insect in amber, fluke eggs in coprolites (fossilised poop), and the pockmarked jaws of some Tyrannosaurus.

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Love it! Awesome thank you :)
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Tommy Leung

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A Vampire's Toolkit
I've written a new Parasite of the Day blog post!
This post is about Colubraria reticulata - a snail that feed on the blood of fish. But how does a snail feed on the blood of an agile animal like a fish, and what kind of adaptations does it have to enable it to live its vampiric lifestyle? Find out in the post below!

Vampires have undergone a lot of image change over the centuries and they are a common part of many culture's mythology. But vampires are also a common part of nature. Blood sucking is a life style found in over 14000 known l...
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Exceptionally freaky & fascinating
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Ghili In The Belly
I have written a new Parasite of the Day blog post! This post is about Artystone trysibia - a parasitic isopod which is found in Amazonian fishes. While it is related to the infamous tongue-biter, the parasitic habit of this species makes its more famous cousin seems almost quaint. Follow the post below to find out more!

The tongue-biter Cymothoa exigua is arguable one of the most (in)famous fish parasite in the world. It was famous enough to get a mention on the Colbert Report, and while the world recoil in collective horror at the sight of ...
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Quelle horreur. ..Vu de près 
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The Worms of Beasts, Tragic Romances, and Body-Snatchers
I have written an end-of-2015 round-up post for the Parasite of the Day blog! A look back on 2015 and some of the fascinating parasite stories that were covered on the blog this year. From pea crabs to kangaroo leeches to hairworms and vampire snails, you'll find links to them all in the post below!

It has been yet another year of parasitology, and this year has been my fifth year writing on a regular basis for Parasite of the Day! So what had been on the parasite menu for 2015? First of all, some of the parasites that ...
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Not so much but thanks
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What Are These? Tapeworms For ANTS?!
I've written a new Parasite of the Day post! This one is about a tapeworm that infects ants and uses them as a way of reaching the woodpecker - the parasite's final host. To facilitate that process, the tapeworm also alter the ant's behaviour and appearance, but by doing so, this seems to also affect the ant's uninfected nestmates. To find out what effects this parasite has on the ant colony as a whole, see the post below!

There are many examples of parasites altering the behaviour of their hosts, and some of them turn their hosts into functionally different animals compared with their uninfected counterparts. When this occurs in highly social ...
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That is the subject of ongoing research, but it might have something to do with the parasite manipulating the muscles of their ant host:
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Tommy Leung

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Zombie Snails And Monster Girls
In addition to doing research on and writing about parasites, sometimes I also draw parasites (you can see some of that in my Creepy but Curious collection here:
However, my enthusiasm for all things parasitological sometimes manifest itself in strange ways, especially when it crossover with some of my other interests... (as you can see here)
See also, a short take on my #sciart  story with parasites: 
For some reason, I decided to draw the infamous zombie snail parasite - Leucochloridium paradoxum - as a monster girl. I think this got started because my friend and I were talking about Monster Mu...
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Sunfish And Flesh Bags
I've written a new Parasite of the Day post! This one is about Accacoelium contortum, a parasitic fluke which lives on the gills of the ocean sunfish ( Mola mola ). While most other flukes live in the intestine of their hosts, this one is a little different, and it seems to have evolved some peculiar adaptations in order to live in its unusual habitat. Find out more in the post below!

Today, we are featuring a parasite that lives on the ocean sunfish (Mola mola) which happens to be the heaviest known living bony fish in the world. One can say that it is a truth universally acknowledged (by myself at least)...
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Tommy's Collections
Evolutionary biologist, parasitologist
Parasitologist, Evolutionary Biologist, Researcher, Lecturer
Parasitologist and evolutionary biologist who also happen to write for a blog about parasites, and likes to draw things sometimes.

I am a biologist who conduct studies on various ecological and evolutionary biology aspects of parasitism/symbiosis. I also write for the Parasite of the Day blog, which I co-administrate with its founder, Susan Perkins of the American Natural History Museum.

Outside of my professional field, my favourite thing to do is drawing - some of which (but not all) are inspired by my scientific work. My drawings can be found on my dA account.
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