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Australia, land of dragons (part II)

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Highly simplified cladogram of the amphibolurine clade that includes Pogona, Ctenophorus and kin, based mostly on the tree in Pyron et al. (2013). Images by Adam Yates (Gowidon), Tony Gamble (Pogona), and Stephen Zozaya (the remainder), used with permission.

Time for more Australian agamids, or amphibolurines, or dragons, whichever you prefer. Last time round, we looked at the water dragons, Moloch and a few other taxa, meaning that ‘all’ that’s left to get through is… the remainder. And there are quite a few of them: bearded dragons, earless dragons, bicycle dragons (yes, really) and so on.

We start with the numerous Ctenophorus species, sometimes termed comb-bearing dragons (for their vaguely comb-like dorsal frills*) or military dragons. This group of mostly terrestrial lizards includes almost 30 small-scaled, long-tailed species that generally have a row of enlarged scales running from below the eye to above the ear and sometimes have the tympanum covered by small scales. There are rock-dwelling and sand-dwelling specialists within the group; some of the latter sprint across (relatively) long distances when threatened and are among the most gracile and fastest-running of Australian lizards. Some species sprint bipedally (Clemente et al. 2008), the crazy-looking rotations of their hindlimbs earning them the popular moniker ‘bicycle-dragon’. And there are those that hide in burrows, those that hide under rocks, and those that hide in vegetation. Phylogenetic studies indicate that each of these lifestyle differences have evolved, independently, at least twice.

* Thanks to Christian Kammerer for confirming that point.

Ring-tailed dragon (Ctenophorus caudicinctus), a swift-running saxicolous dragon, conventionally split into more than five subspecies. Image (c) Stephen Zozaya, used with permission.

As with several amphibolurine genera, the number of recognised species within Ctenophorus has increased notably in the last few decades. At the time of writing, the newest is the Barrier Range dragon C. mirrityana from New South Wales, named late in 2013. Another recently named one, C. nguyarna Doughty et al., 2007 from Lake Disappointment in Western Australia, is a specialist denizen of salt lake habitat, as is the Lake Eyre dragon C. maculosus of South Australia.

Montage showing some of the diversity within Ctenophorus. From top: the tiny dune specialist C. femoralis, the splendidly marked Military dragon (C. isolepis), and a gravid Central netted dragon (C. nuchalis). Images (c) Stephen Zozaya, used with permission.

Like some other amphibolurines (those included within the problematic taxon Lophognathus), an erectile dorsal crest is present in some species. Prominent lateral and/or ventral markings and brightly coloured throats are present in many species (most usually in the males alone): some are boldly patterned and really attractive. There has been substantial interest in sexual selection and sociosexual behaviour in these lizards: in some, the males are territorial and are highly aggressive in their treatment of females. This is best known in the Lake Eyre dragon, a species in which females will even flip onto their backs in order to avoid forced copulation.

Members of the group are also unusual in lacking a phalanx from the fifth toe (a feature also seen in Moloch and some Tympanocryptis species). Some of the smaller species only produce two eggs per clutch – a massive contrast to the relatively huge clutches produced by some other amphibolurines (up to 35 in Pogona) and a reminder of how variable clutch size can be within a clade. Also remarkable is how short-lived some of them are: they are apparently ‘annuals’ that are sexually mature by 10 months of age, and rarely survive into their second year. This is true for small species as well as for the relatively large Central netted dragon C. nuchalis.

The beautiful Central netted dragon (Ctenophorus nuchalis), a short-snouted, widespread dragon with a fine, dark brown reticulated pattern. Image (c) Stephen Zozaya, used with permission.

Some studies find the Ctenophorus dragons to form a clade, and to be the sister-taxon to the amphibolurine clade that includes Lophognathus, Chlamydosaurus, Diporiphora and so on (Pyron et al. 2013). Some molecular work indicates that Rankinia – the heath dragons – is nested within Ctenophorus (Melville et al. 2001, Clemente et al. 2008), a discovery that has led to the idea that the name should be dropped from use. However, Melville et al. (2011) found Rankinia to be well away from Ctenophorus, and close to Diporiphora.

Those graceful diporiphorans

The relationships between the remaining amphibolurines vary quite a bit from one study to the next. Tympanocryptis (earless dragons), Pogona (bearded dragons) and Diporiphora all seem to be close relatives (Macey et al. 2000, Hugall et al. 2008, Melville et al. 2011, Pyron et al. 2013) but the exact nature of their relationship is controversial as is the monophyly of several of these genera. Caimanops amphibolurodes – the Mulga dragon, the only member of its genus – was recently returned to synonymy with Diporiphora by Doughty et al. (2012) since it’s surrounded by Diporiphora species in phylogenetic trees. Doughty et al. (2012) also re-synonymised the Wells and Wellington names Mantichosaurus and Houstoniasaurus with Diporiphora.

Two-lined dragon (Diporiphora bilineata), a climbing species of northern Australia (and perhaps New Guinea); image (c) Stephen Zozaya, used with permission.

Three more diporiphoran dragons. From top: Diporiphora nobbi, D. phaeospinosa, and D. vescus. Images (c) Stephen Zozaya, used with permission.

A recent molecular study of the Diporiphora dragons indicated that most divergences within this group occurred during the Late Miocene (Edwards & Melville 2011). This discovery suggests that their diversification was linked to the climatic changes that occurred at this time – their adaptation to dry woodlands and similar habitats in particular being driven by these events. Given how insanely gracile and long-tailed some Diporiphora dragons are, it’s kinda pleasing to imagine them as stretched out, highly modified versions of the more terrestrial, stout-bodied ‘core’ amphibolurines like Pogona. Diporiphora dragons frequently climb in tussocks, shrubs and slender-branched trees.

Several of the Diporiphora species, including the semi-arboreal, green D. superba of the Kimberley region (named as recently as 1974) and the reddish-brown D. valens (named in 1979), have tails that are 300-400% SVL*. Incidentally, having noticed how recently named those two species are, it’s worth saying that most Diporiphora dragons are recently named. Check this out: D. convergens Storr, 1974, D. lalliae Storr, 1974, D. linga Houston, 1977, D. magna Storr, 1974, D. pindan Storr, 1979 and D. reginae Glauert, 1959, D. phaeospinosa Edwards & Melville, 2011, D. vescus Doughty et al., 2012, D. adductus Doughty et al., 2012 and D. paraconvergens Doughty et al., 2012. Diporiphora dragons – I’ve taken to calling them diporiphorans, since there doesn’t seem to be a handy, vernacular term in widespread use – are widely distributed across Australia (except the south-east) and one species inhabits New Guinea.

* snout to vent length.

The bearded dragons

Dwarf bearded dragon (Pogona minor), a semi-arboreal Pogona that lacks many of the spines present in other Pogona species. Image (c) Stephen Zozaya, used with permission.

Bearded dragons (Pogona) are terrestrial and semi-arboreal amphibolurines that have a somewhat compressed body and a proportionally short tail with laterally projecting spines on either side of the base. Bearded dragons owe their name to an expandable throat pouch, or ‘beard’, covered on all sides with erectile spines. This structure is erected as the long, curved first and second ceratohyal bones are pulled downwards and outwards by the attached anterior mandibular muscles. Within the group, P. barbata has an especially specialised hyoid mechanism, the second ceratohyal having a modified, simplified form relative to that of other Pogona species (Throckmorton et al. 1985). Like most amphibolurines, bearded dragons are predominantly insectivorous but some species (like P. barbata) eat flowers, soft leaves and fruit on occasion.

How ceratohyal depression and spreading causes expansion of Pogona's 'beard'. Series of illustrations from Throckmorton et al. (1985).

About eight species are recognised, the most familiar of which is of course the Central bearded dragon P. vitticeps, well known thanks to the pet trade. The majority of pet Central bearded dragons are of the standard ‘wild type’, but it’s becoming increasingly well known that people have created several remarkable forms through selective breeding: there are now giant bearded dragons, forms with reduced or smooth scalation termed leatherbacks and silkbacks, ‘translucent’ form with reduced pigmentation, ‘Witblits’ forms that essentially lack all patterning, the also patternless ‘silverbacks’ , and numerous colour morphs. We have created domesticated lizards that do not exist in nature.

The 7th edition is here... the 6th edition is 14 years old now, so much has changed.

Ok: in this and the previous article I’ve discussed most of Australian dragon diversity… but not all of it. There are still lineages that I didn’t cover (Amphibolurus in particular), and numerous species I didn’t even mention. So, there’s loads more to do. Oh well, maybe next time. And – while I’m here…. who else is excited about the impending publication of the Seventh Edition of Cogger’s Reptiles and Amphibians of Australia?

Thanks again to Adam Yates (who blogs at A Fragment of Gondwana), Tony Gamble and especially Stephen Zozaya (who blogs at Saurian Obsessions) for their help in providing images.

For previous Tet Zoo articles on agamids and other iguanian lizards, see…

Refs – -

Clemente, C. J., Withers, P. C., Thompson, G. & Lloyd, D. 2008. Why go bipedal? Locomotion and morphology in Australian agamid lizards. The Journal of Experimental Biology 211, 2058-2065.

Doughty, P., Kealley, L. & Melville, J. 2012. Taxonomic assessment of Diporiphora (Reptilia: Agamidae) dragon lizards from the western arid zone of Australia. Zootaxa 3518, 1-24.

Edwards, D. L. & Melville, J. 2011. Extensive phylogeographic and morphological diversity in Diporiphora nobbi (Agamidae) leads to a taxonomic review and a new species description. Journal of Herpetology 45, 530-546.

Hugall, A. F., Foster, R., Hutchinson, M. & Lee, M. S. Y. 2008. Phylogeny of Australasian agamid lizards based on nuclear and mitochondrial genes: implications for morphological evolution and biogeography. Biological Journal of the Linnean Society 93, 343-358.

Macey, J. R., Schulte, J. A., Larson, A., Ananjeva, N. B., Wang, Y., Pethiyagoda, R., Rastegar-Pouyani, N. & Papenfuss, T. J. 2000. Evaluating trans-Tethyan migration: an example using acrodont lizard phylogenetics. Systematic Biology 49, 233-256.

Melville, J., Schulte, I. & Larson, A. 2001. A molecular phylogenetic study of ecological diversification in the Australian lizard genus Ctenophorus. Journal of Experimental Zoology 291, 339-353.

Pyron, R. A., Burbrink, F. T. & Wiens, J. J. 2013. A phylogeny and revised classification of Squamata, including 4161 species of lizards and snakes. BMC Evolutionary Biology 2013, 13:93 doi:10.1186/1471-2148-13-93

Throckmorton, G. S., Bavay, J. D., Chaffey, W., Merrotsy, B., Noske, S. & Noske, R. 1985. The mechanism of frill erection in the bearded dragon Amphibolurus barbatus with comments on the jacky lizard Amphibolurus muricatus (Agamidae). Journal of Morphology 183, 285-292.

Darren Naish About the Author: Darren Naish is a science writer, technical editor and palaeozoologist (affiliated with the University of Southampton, UK). He mostly works on Cretaceous dinosaurs and pterosaurs but has an avid interest in all things tetrapod. His publications can be downloaded at He has been blogging at Tetrapod Zoology since 2006. Check out the Tet Zoo podcast at! Follow on Twitter @TetZoo.

The views expressed are those of the author and are not necessarily those of Scientific American.

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  1. 1. ekocak 8:43 am 02/7/2014

    First, regarding domesticated lizards: See also, leopard geckos (Eublepharis macularius), which not only have a ridiculous number of color morphs but also giantism.

    Second, One thing I was particularly struck with, being more familiar with North American herpetofauna, is how convergent many of these look with lizards here. Ctenophorus caudicinctus particularly looks like a collared lizard, and even has similar dimorphism. Very cool.

    Thirdly, Lake Disappointment? I’m moving there just for the mailing address.

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  2. 2. andrewwright73 11:01 am 02/7/2014

    Nit pick: In the wonderful picture of the Central netted dragon you’ve listed it as Centrophorus not Ctenophorus.

    Great article! Keep ‘em coming…What happened to the crocodile skulls ;-)

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  3. 3. Heteromeles 11:48 am 02/7/2014

    Don’t bug him about the croc skulls. I’m sure he’s saving it for the one year anniversary of that question.

    Neat article

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  4. 4. BrianL 12:07 pm 02/7/2014

    Ah, the wonders of selective breeding in domesticated species! I am often amazed by how much diversity has by now been bred in numerous species more or less readily available in captivity. What I always find particularly interesting is how it is this breeding that truly drives the malleability of a certain bauplan to the extreme, farther than it normally would in nature, at least within a species and so short a period of time. While I think it is understandable that discussion of diversity of clades tends to ignore any domesticated diversity that exists, I do think it also qualifies as something of an ommission to more or less pretend some of the most extreme varieties do not exist, simply because they aren’t wild. Is there any work available that truly covers the breadth of domesticated animals in general in any serious depth? I get the impression one would need to collect various high quality monographs discussing a single domesticated species each for that.

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  5. 5. Heteromeles 4:00 pm 02/7/2014

    @Brian: I’m pretty sure there isn’t. You can find books like the Encyclopedia of Historic and Endangered Livestock and Poultry Breeds, which is what it says on the cover. Note that this doesn’t cover the current commercial breeds, but it covers the rare ones.

    Since I have friends who have worked with species undergoing adaptive radiation (in this case, Hawaiian tarplants and lobeliads), I should note that doing research on closely related, recently derived lineages is, shall we say, fraught, especially if you’re trying to find genetic markers to help you understand the relationships among breeds. This is the kind of thing that destroys grad students’ lives, as they spend all their grant money and time chasing one false lead after another. Some have even taken out personal loans to try to finish the research. It isn’t pretty.

    The other thing to remember is that breeders also deliberately hybridize and back-cross to get the forms they want, so it’s reasonable to assume that the gene-trees will diverge and not necessarily coalesce into a unified cladogram for the species.

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  6. 6. BrianL 4:20 pm 02/7/2014

    Thank you but I was not referring to cladograms as much as physical diversity in various domesticated species. I suppose I’m more interested in overall diversity and the extremes of human-led selective breeding than in the details of their phylogeny. I would thus be interested in those commercial breeds that the book you mentioned ignores, since those, along with ornamental breeds, are probably the most extreme ones.

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  7. 7. Heteromeles 4:46 pm 02/7/2014

    Actually, check out the book, because the current commercial breeds are a small proportion of the total diversity of each domestic species, for just about any species you name aside from cannabis.

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  8. 8. SciaticPain 5:19 pm 02/7/2014

    Interesting I have never considered that the pet trade has created basically domesticated lizards in the case of bearded dragons. It makes sense as the tropical fish trade, especially for cichlids, has done the same to many varieties. Maybe such a docile, omnivorous critter would make an ideal food animal in an increasingly drought stricken, erratic weather future?

    Duane Nash

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  9. 9. Christopher Taylor 6:53 pm 02/7/2014

    Lake Disappointment? I’m moving there just for the mailing address.

    Don’t. It’s called that for a reason.

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  10. 10. Allen Hazen 12:14 am 02/8/2014

    Seriously off-topic (though maybe I could point to the discussion above of domesticated forms as a kind-of connection), but… One of the Tet Zoo Version One blogs that fascinated me was about the origins of the (domestic) dog and just how it was related to wolves: I’d love it if you chose to revisit that topic some time. It seems to me that there has been a bit of relevant research since, including this a link to which was on the SciAm page with your blog today (7.ii.2014).

    One of the fascinating suggestions of the Version One discussion was that the wild ancestor of the domestic dog, though more closely related to wolves than to other wild canids (Konrad Lorentz was just WRONG about jackals and the ancestry of dogs), might have been a very different sort of animal, morphologically and behaviourally, from the “classic” wolf of Boreal Eurasia. And the stuff that has come out since seems to my non-expert eye to be at least consistent with that suggestion.

    (And, again, apologies for an off-topic comment.)

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  11. 11. naishd 7:13 am 02/8/2014

    Lake Disappointment is so named because it’s a big salt pan (it was named by Frank Hann in 1897, his hope of course being that it was a great expanse of fresh water) that’s dry outside except during exceptionally wet times. I think it’s only been water-filled a few times since its discovery. Still, it’s home to a neat dragon, and to loads of waterbirds when filled with water. Some of the saltlake-dwelling dragons inhabit burrows below the salt crust. They must be really tough.

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  12. 12. naishd 7:23 am 02/8/2014

    Re: comment 10 (on alternative hypotheses about dog ancestry) – I’ve often thought about re-vamping that article but haven’t for a few reasons. One is that a ton of new work has been done that needs to be incorporated, and which very much contradicts the main premise of the argument. Another is that it pissed off a few researchers that I think very highly of – they argue (with justification, I think) that the argument is highly selective and ignores key bits of data.

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  13. 13. RoryD 12:27 pm 02/8/2014

    Thank you for writing these two fascinating articles on one of my favourite lizard groups.

    It’s interesting that you say only a few species of bearded dragons occassionally eat plant matter. Given that P.vitticeps in captivity is known for becoming increasingly herbivorous as it grows until this becomes its primary diet, Does it have an extreme diet compared to others in the wild?

    Regarding domestication, agamas and particularly p.vitticeps are also renowned by exotics enthusiasts for their ‘affection’ and intelligence compared to other lizards (along with teguxins and monitors). I wonder if “Intellegama” from the previous post could be a reference to this? Perhaps unlikely.

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  14. 14. vdinets 12:44 pm 02/8/2014

    BrianL (#4): I once co-authored such a book (with E. Rotshild), but it was in Russian (Domestic Animals, ABF, Moscow, 1997 and subsequent editions).

    Allen Hazen (#10): the idea that the split between wolf and dog pre-dates the domestication of the latter is rather old, and I haven’t seen any evidence against it whatsoever; in fact, all recent findings fit into it very well. I wrote a little essay on the issue as a course paper back in 2007 ( All new research published since 2007 also seems to support the idea, even though the authors don’t always realize it themselves.

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  15. 15. ekocak 1:04 pm 02/8/2014

    Here’s a pretty good breakdown of bearded dragon morphs in the reptile hobby (The pictures are small, but you can get some idea of the huge range of colors people have bred):

    The same is also now true of ball pythons (Python regius) on the snake side of things.
    Also of note, it seems as though New Caledonian crested geckos (Correlophus ciliatus), which have surged in popularity since their rediscovery in the early 90′s, are somehow more resistant to this sort of thing. In all that time, no one has managed to produce an albino or leucistic animal, although its possible it has something to do with the fact that all of the pet trade animals are descended from about 200 individuals. Someone did recently produce a piebald one:

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  16. 16. Allen Hazen 7:19 pm 02/8/2014

    V. Dinets–
    Thanks for the link to your paper!
    One bit of new research since you wrote it that comes to mind: I think that in the last year (so, 2013) genetic research was published confirming the link between the North Carolina dogs (distinct behaviourally from “standard” domestic dogs, and– though not always the right colour– similar to dingoes in appearance) and dingoes.

    The smaller brains of dogs, vis-a-vis wolves: could this be a regular consequence of domestication? I recall a few years ago a published claim that domestic cats have significantly fewer neurones in their brains than closely related wild felids.

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  17. 17. vdinets 9:33 pm 02/8/2014

    Allen Hazen: the most interesting bits were the recent discoveries of remnant Gray Wolf populations in Ethiopia and North Africa.

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  18. 18. Andreas Johansson 6:06 am 02/9/2014

    Allen Hazen wrote:

    I recall a few years ago a published claim that domestic cats have significantly fewer neurones in their brains than closely related wild felids.

    I’m of the impression that neural reduction is a “standard” consequence of domestication, seen in most or all domesticates, but I don’t have a reference at hand.

    (That modern humans have smaller brains than Neanderthals or Cro Magnon has been cited in favour of the idea that humans have “self-domesticated”.)

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  19. 19. naishd 11:46 am 02/9/2014

    Dammit, thread on lizards gets hijacked by thoughts on dog domestication :) …..

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  20. 20. ectodysplasin 1:39 pm 02/9/2014

    re: “domestic” lizards,

    It’s worth pointing out that a lot of these “domestic varieties” are really just single gene mutations that have been isolated with inbreeding, and likely do not represent true domestication.

    In addition, the inbreeding does some pretty nasty things to a lot of these selective lines. The scaleless forms, for example, tend to show some serious dorsoventral patterning problems and I’ve heard anecdote that they exhibit some serious neurological problems.

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  21. 21. ectodysplasin 1:53 pm 02/9/2014


    iven that P.vitticeps in captivity is known for becoming increasingly herbivorous as it grows until this becomes its primary diet, Does it have an extreme diet compared to others in the wild?

    This is the case for most herbivorous lizards. Fast growth is difficult with a plant-only diet, so most juvenile herbivorous lizards have a more catholic diet and then grow into herbivory as they reach adult size.

    This probably is also related in part to minimum size constraints on gut size for processing foliage.

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  22. 22. naishd 4:55 pm 02/9/2014

    Wolves in Africa (comment # 17): I spent time in Libya looking for evidence for ‘Canis aureus lupaster‘, the long-controversial canid thought at the time to be a Golden jackal but now regarded as a wolf. Have a half-finished article on these animals that I might finish one day…

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  23. 23. BilBy 6:58 pm 02/9/2014

    Darren – an article on Canis aureus lupaster would be great: waiting with bated breath for finished article

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  24. 24. Heteromeles 7:35 pm 02/9/2014

    Actually, the idea of domesticated reptiles is a decent one for discussion. So far as I know, there aren’t any, although one could make an argument that Hemidactylus frenatus is at least a human commensal. What would it take to make a reptile a true human symbiont, aka a domesticated species?

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  25. 25. John Scanlon FCD 2:54 am 02/10/2014

    What would it take? – at least, more or less complete reproductive isolation from wild populations. ‘Domestic’ entails human control over survival and reproduction at all stages of life, but not only that. Spanish fighting bulls should probably not be described as domestic.
    Cobras are an important commensal in some places and times (rat control allows grain storage allows civilization), but I don’t think they’ve been domesticated anywhere. Not even as much as cats. Don’t know much about the snake farming industry in China, though.

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  26. 26. Chabier G. 4:35 am 02/10/2014

    John: Spanish fighting bull is a true domestic animal, it’s a polyphyletic breed, descending from the worst minded badass bulls of several Iberian breeds.Then, it’s not the last survivor of Iberian Aurochs or anything like, as bullfighting advocates are keen to say. The singularity of this bulls is that they aren’t selected searching for meat or milk production, but for fighting skills. But they are managed, guided, selected and vaccinated as any other breed (but with a little more caution).

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  27. 27. Dartian 5:09 am 02/10/2014

    Vlad, in that article of yours, you say this:

    Some features of dog anatomy, particularly brain structure, resemble jackals and coyotes, but not wolves.

    What’s the original reference for that claim?

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  28. 28. naishd 5:38 am 02/10/2014

    Regarding the fact that those captive bearded lizard strains are only different from wild ones due to one gene (see comment # 20), I’ve been trying to find out (though, not trying all that hard) how different domestic cats are (in genetic terms) from their wild relatives. It’s all down to just a few genes, isn’t it?

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  29. 29. RoryD 7:01 am 02/10/2014

    I’m aware of the metabolic/anatomical constraints going on. I just wondered whether P.vitticeps were especially herbivorous bearded dragons or not.

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  30. 30. ekocak 8:57 am 02/10/2014

    Isn’t this sort of arguing about the semantics of the word “domestication”? I always took it to mean “Cannot survive in the wild without human intervention, specifically because of human tinkering.” I didn’t realize there was a quantity of genes that mattered.

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  31. 31. Andreas Johansson 10:09 am 02/10/2014

    “Cannot survive in the wild without human intervention, specifically because of human tinkering.”

    That would seem to exclude dogs (or at least certain breeds). Feral dogs are common after all.

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  32. 32. ekocak 10:19 am 02/10/2014

    Good point, definitely. But my thought kinda still stands: domestication doesn’t seem to be a binary, on or off after x number of mutations kind of thing.

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  33. 33. vdinets 12:08 pm 02/10/2014

    Dartian: I can’t remember why there is no reference in the text. The issue of dog brains is discussed in detail in Domestication: The Decline of Environmental Appreciation by Helmut Hemmer, Cambridge Univ. Press, 1990.

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  34. 34. Tayo Bethel 12:17 pm 02/10/2014

    It’s surprising how just a few genes can produce animals of quite different appearance and temperaments. Felis sylvestris is a case in point. Eurasian wildcats and domestic cats can interbreed, yet the two have markedly different temperaments–the domestic tat, relatively easygoing (as a very general rule) versus the Eurasian wildcat’s oft-noted aggressive tendencies. The domestic cat’s ancestor, seems to have been shy but not nearly as aggressive as its sylvestris sylvestris counterpart.
    (Incidentally, according to the literature, African(or at least North African) wildcats raised in captivity can bond with familiar humans if raised by them but are fearful of strangers.

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  35. 35. David Marjanović 1:13 pm 02/10/2014

    Another is that it pissed off a few researchers that I think very highly of – they argue (with justification, I think) that the argument is highly selective and ignores key bits of data.

    All the more reason to publish a corrected update! :-)

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  36. 36. Heteromeles 3:46 pm 02/10/2014

    I should point out at this juncture that reproductive isolation of domestic species is best achieved when the wild relatives are either extinct or on another continent. Dogs can interbreed with wolves and coyotes (among other canids), domestic cats can interbreed with wildcats, pigs with boars, and so forth.

    According to Gary Nabhan in Enduring Seeds, the Tepehuans in Nabogame Mexico regularly interbreeds maize with teosinte to make hardier maize, and plant breeders normally go to wild conspecifics to look for disease resistance genes for domestic plants. If corn isn’t domesticated, I don’t know what is.

    As for domestic cats, if a cat is black and white, drinks milk as an adult, and happily (and peacefully) lives with humans, dogs, and chickens, I’m going to start giggling when people say it’s not domesticated, merely tamed. What more do you need?

    As ekocak noted, domestication isn’t anything like binary.

    So let’s start again: what would we need to have a domesticated reptile? Something that drinks milk and plays nice with cats or chickens?

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  37. 37. naishd 5:40 pm 02/10/2014

    In case anyone misunderstood the question I was asking about cat genetics (comment # 28), I was trying to get some idea of how close (or far) an obvious domesticate is from its very similar wild ancestor… not trying to establish a ‘domestication index’ based on genetic distance.

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