Last night a thought occurred to me, and I wrote to Matt:
If birds had gone extinct 66 Mya along with all the other dinosaurs, would it ever have occurred to us that they had flow-through lungs? Is there — can there be, outside of amazing soft-tissue preservation — any way for bone fossils to tell us about this?
(Yes, we have evidence for air-sacs in the pneumatization of vertebrae and other bones, but I doubt that would have led us to the idea of the flow-through lung. I’m not even convinced it would have led us to the idea of air-sacs, if we didn’t have extant birds as a model.)
Matt wrote back and gave me permission to write up his reply into an SV-POW! post, which you are now, obviously, reading. Here’s what he said.
No, we’d have no idea about the flow-through lungs from fossils.
In fact, it’s particularly bad for birds. Big saurischian dinosaurs had lots of postcranial skeletal pneumaticity (PSP), and some extant birds have a lot of PSP, but most Mesozoic birds have limited to zero diagnostic PSP. A few have some external foramina on the vertebrae that might be pneumatic, but might just be lateral foramina for the equatorial arteries. It doesn’t help that most Mesozoic birds are smashed flat and often have other elements overlapping the vertebrae — most often the proximal portions of their own ribs.
So ironically, even if we somehow came up with the stacked notions that (1) PSP implied air sacs, and (2) air sacs implied flow-through lungs, we’d be much more likely to infer flow-through lungs in Diplodocus and Tyrannosaurus than in Archaeopteryx or most other Mesozoic birds.
But wait, it gets worse! The work by Colleen Farmer, Emma Schachner, and colleagues that demonstrated unidirectional flow in the lungs of crocs, monitor lizards, and iguanas would presumably still get done, but those animals have flow-through lungs without PSP and without particularly elevated metabolisms (although monitors are trying hard). Without the example of birds showing us how that primitive flow-through system can be further refined and supercharged to power tachymetabolism, we’d still learn of flow-through lungs, but we’d have no reason to connect them to PSP or any particular metabolic strategy.
I’ve probably mentioned this before, but it really irks me that we assume that birds are the pinnacle of lung evolution. Why? Birds survived the K/Pg extinction because they were small and could hide and eat seeds and grubs for a while, not because they had better lungs than everything else (otherwise mammals, lizards, etc. would have done even worse). To me it would be a heck of a coincidence if the one group of ornithodirans that survived — for reasons unrelated to lung function — just happened to have the most efficient lungs. It’s always been tantalizing to me that extant birds start out with 12 embryonic air sacs, which through development usually merge into the usual 9 (unpaired clavicular, and paired cervical, anterior thoracic, posterior thoracic, and abdominal sacs). This seems like an embryonic footprint of a greater diversity — and possibly even a greater complexity — of respiratory anatomy in the ancestral ornithodiran, saurischian, or theropod (or all of the above).
Skull audit: Wedel responds
February 9, 2022
Left to right: alligator, beaver, black bear, armadillo, cat, ostrich. I know, the archosaurs aren’t mammals, and the alligator isn’t even a skull. But if you can’t have a lounge lizard crash your mammal skull party, what are you even doing with your life? Not pictured: about four rabbit skulls I forgot I had boxed up, plus a couple of turtles (yeah, yeah) sitting on a friend’s desk, in their locked office.
It warmed my crooked little heart to see Mike Taylor, noted sauropodologist and disdainer-of-mammal-heads, return mammal skulls to the blog’s front page yesterday. Naturally I had to support my friend and colleague in this difficult time, when he may be experiencing confusing feelings regarding nasal turbinates, multi-cusped teeth, and the dentary-squamosal jaw joint.
My skull collection is split across home and office, but I had to go in to campus this afternoon for a video recording thing, so I got most of the office set, shown above, on that jaunt.
After the workday ended, I had just enough time before the light faded to assemble and photograph the home collection:
Back row: peccary, pig, deer, sheep, dog. Middle row: opossum, rabbit. Front row: opossum, marten (both hemisected). Not pictured: emergency backup sheep, moar rabbits
I’ve blogged about the bear, the pig, and the hemisected skulls, but I think that’s it. I should do more skull blogging, most of these have a story:
- I prepped the armadillo, cat, rabbit, and sheep skulls myself (besides the bear and pig). The first two I found in the woods, the mostly-decomposed rabbit was a gift from my father-in-law, and the sheep head I obtained from the market down the street ($10, and I ate the meat).
- The alligator head and deer skull were gifts, from Vicki and from my brother Ryan, respectively.
- The rest I purchased here and there over the years, usually when they were on deep discount. The peccary is a memento of a trip to Big Bend back in 2007 (I bought it at a taxidermy shop a long way outside the national park), and the dog came from the seconds bin at the Museum of Osteology — I plan to saw off the top of the braincase to see the cranial nerve exits, just as in the preparation by Peter Dodson shown in this post.
I have more heads awaiting skull-ization in various freezers, too. Couple more pig heads at work, and at the house a strategic reserve sheep head, plus skunk, squirrel, and rat. Plus a partially-mummified but mostly defleshed armadillo whose saga deserves a detailed recounting:
NB: the stray bits toward the bottom of the image are from a cat. Mr. Armadillo’s limb bones and vertebrae are still in the armadillo kit.
In the first comment on Mike’s post yesterday, I expressed envy that he had the better skull collection. After pulling together all my critters, I think I just have a worse memory. In my defense, it’s been almost two years since I was in the office regularly, and about half the skulls in the home collection are recent-ish acquistions (~last three years), so a lot of stuff had either fallen out of memory or not gotten properly established yet. But Mike has definitely prepped more — and more exotic — skeletons, and it was his enthusiastic collecting and blogging of dead animal bits that inspired me to start my recent-ish spate of skull preparations. More to come on that front as time and opportunity allow, probably starting with this:
Good experiences of peer-review at Qeios
March 9, 2021
A month after I and Matt published our paper “Why is vertebral pneumaticity in sauropod dinosaurs so variable?” at Qeios, we were bemoaning how difficult it was to get anyone to review it. But what a difference the last nineteen days have made!
In that time, we’ve had five reviews, and posted three revisions: revision 2 in response to a review by Mark McMenamin, version 3 in response to a review by Ferdinand Novas, and version 4 in response to reviews by Leonardo Cotts, by Alberto Collareta, and by Eduardo Jiménez-Hidalgo.
Taylor and Wedel (2021: Figure 2). Proximal tail skeleton (first 13 caudal vertebrate) of LACM Herpetology 166483, a juvenile specimen of the false gharial Tomistoma schlegelii. A: close-up of caudal vertebrae 4–6 in right lateral view, red circles highlighting vascular foramina: none in Ca4, two in Ca5 and one in Ca6. B: right lateral view. C: left lateral view (reversed). D: close-up of caudal vertebrae 4–6 in left lateral view (reversed), red circles highlighting vascular foramina: one each in Ca4, Ca5 and Ca6. In right lateral view, vascular foramina are apparent in the centra of caudal vertebrae 5–7 and 9–11; they are absent or too small to make out in vertebrae 1–4, 8 and 12–13. In left lateral view (reversed), vascular foramina are apparent in the centra of caudal vertebrae 4–7 and 9; they are absent or too small to make out in vertebrae 1–3, 8, and 10–13. Caudal centra 5–7 and 9 are therefore vascularised from both sides; 4 and 10–11 from one side only; and 1–3, 8 and 12–13 not at all.
There are a few things to say about this.
First, this is now among our most reviewed papers. Thinking back across all my publications, most have been reviewed by two people; the original Xenoposeidon description was reviewed by three; the same was true of my reassessment of Xenoposeidon as a rebbachisaur, and there may have been one or two more that escape me at the moment. But I definitely can’t think of any papers that have been under five sets of eyes apart from this one in Qeios.
Now I am not at all saying that all five of the reviews on this paper are as comprehensive and detailed as a typical solicited peer review at a traditional journal. Some of them have detailed observations; others are much more cursory. But they all have things to say — which I will return to in my third point.
Second, Qeios has further decoupled the functions of peer review. Traditional peer review combines three rather separate functions: A, Checking that the science is sound before publishing it; B, assessing whether it’s a good fit for the journal (often meaning whether it’s sexy enough); and C, helping the authors to improve the work. When PLOS ONE introduced correctness-only peer-review, they discarded B entirely, reasoning correctly that no-one knows which papers will prove influential[1]. Qeios goes further by also inverting A. By publishing before the peer reviews are in (or indeed solicited), it takes away the gatekeeper role of the reviewers, leaving them with only function C, helping the authors to improve the work. Which means it’s no surprise that …
Third, all five reviews have been constructive. As Matt has written elsewhere, “There’s no way to sugar-coat this: getting reviews back usually feels like getting kicked in the gut”. This is true, and we both have a disgraceful record of allowing harshly-reviewed projects to sit fallow for far too long before doing the hard work of addressing the points made by the reviewers and resubmitting[2].
The contrast with the reviews from Qeios has been striking. Each one has sent me scampering back to the manuscript, keen to make (most of) the suggested changes — hence the three revised versions that I’ve posted in the last fortnight. I think there are at least two reasons for this, a big one and a small one.
- The big reason, I think, is that the reviewers know their only role is to improve the paper. Well, that’s not quite true: they also have some influence over its evaluation, both in what they write and in assigning a 1-to-5 star score. But they know when they’re writing their reviews that whatever happens, they won’t block publication. This means, firstly, that there is no point in their writing something like “This paper should not be published until the authors do X”; but equally importantly, I think it puts reviewers in a different and more constructive mindset. They feel themselves to be allies of the authors rather than (as can happen) adversaries.
- The smaller reason is it’s easier to deal with one review at a time. I understand why journals solicit multiple reviews: so the handling editor can consider them all in reaching a decision. I understand why the authors get all the reviews back at once. But that process can’t help but be discouraging: because, once the decision has been made, they’re all on hand and there’s no point in stringing them out. One at a time may not be better, exactly; but it’s emotionally easier.
Is this all upside? Well, it’s too early to say. We’ve only done this once. The experience has certainly been more pleasant — and, crucially, much more efficient — than the traditional publishing lifecycle. But I’m aware of at least two potential drawbacks:
First, the publish-first lifecycle could be exploited by cranks. If the willingness to undergo peer-review is the mark of seriousness in a researcher — and if non-serious researchers are unwilling to face that gauntlet — then a venue that lets you make an end-run around peer-review is an obvious loophole. How serious a danger is this? Only time will tell, but I am inclined to think maybe not too serious. Bad papers on a site like Qeios will attract negative reviews and low scores, especially if they start to get noticed in the mainsteam media. They won’t be seen as having the stamp of having passed peer-review; rather, they will be branded with having publicly failed peer-review.
Second, it’s still not clear where reviewers will come from. We wrote about this problem in some detail last month, and although it’s worked out really well for our present paper, that’s no guarantee that it will always work out this well. We know that Qeios itself approached at least one reviewer to solicit their comments: that’s great, and if they can keep doing this then it will certainly help. But it probably won’t scale, so either a different reviewing culture will need to develop, or we will need people who — perhaps only on an informal basis — take it on themselves to solicit reviews from others. We’re interested to see how this develops.
Anyway, Matt and I have found our first Qeios experience really positive. We’ve come out of it with what I think is a good paper, relatively painlessly, and with much less friction than the usual process. I hope that some of you will try it, too. To help get the process rolling, I personally undertake to review any Qeios article posted by an SV-POW! reader. Just leave a comment here to let me know about your article when it’s up.
Notes
[1] “No-one knows which papers will prove influential”. As purely anecdotal evidence for this claim: when I wrote “Sauropod dinosaur research: a historical review” for the Geological Society volume Dinosaurs: A Historical Perspective, I thought it might become a citation monster. It’s done OK, but only OK. Conversely, it never occurred to me that “Head and neck posture in sauropod dinosaurs inferred from extant animals” would be of more than specialist interest, but it’s turned out to be my most cited paper. I bet most researchers can tell similar stories.
[2] One example: my 2015 preprint on the incompleteness of sauropod necks was submitted for publication in October 2015, and the reviews[3] came back that same month. Five and a half years later, I am only now working on the revision and resubmission. If you want other examples, we got ’em. I am not proud of this.
[3] I referred above to “harsh reviews” but in fact the reviews for this paper were not harsh; they were hard, but 100% fair, and I found myself agreeing with about 90% of the criticisms. That has certainly not been true of all the reviews I have found disheartening!
We’ve noted many times over the years how inconsistent pneumatic features are in sauropod vertebra. Fossae and formamina vary between individuals of the same species, and along the spinal column, and even between the sides of individual vertebrae. Here’s an example that we touched on in Wedel and Taylor (2013), but which is seen in all its glory here:
Taylor and Wedel (2021: Figure 5). Giraffatitan brancai tail MB.R.5000, part of the mounted skeleton at the Museum für Naturkunde Berlin. Caudal vertebrae 24–26 in left lateral view. While caudal 26 has no pneumatic features, caudal 25 has two distinct pneumatic fossae, likely excavated around two distinct vascular foramina carrying an artery and a vein. Caudal 24 is more shallowly excavated than 25, but may also exhibit two separate fossae.
But bone is usually the least variable material in the vertebrate body. Muscles vary more, nerves more again, and blood vessels most of all. So why are the vertebrae of sauropods so much more variable than other bones?
Our new paper, published today (Taylor and Wedel 2021) proposes an answer! Please read it for the details, but here’s the summary:
- Early in ontogenly, the blood supply to vertebrae comes from arteries that initially served the spinal cord, penetrating the bone of the neural canal.
- Later in ontegeny, additional arteries penetrate the centra, leaving vascular foramina (small holes carrying blood vessels).
- This hand-off does not always run to completion, due to the variability of blood vessels.
- In extant birds, when pneumatic diverticula enter the bone they do so via vascular foramina, alongside blood vessels.
- The same was probaby true in sauropods.
- So in vertebrae that got all their blood supply from vascular foramina in the neural canal, diverticula were unable to enter the centra from the outside.
- So those centra were never pneumatized from the outside, and no externally visible pneumatic cavities were formed.
Somehow that pretty straightforward argument ended up running to eleven pages. I guess that’s what you get when you reference your thoughts thoroughly, illustrate them in detail, and discuss the implications. But the heart of the paper is that little bullet-list.
Taylor and Wedel (2021: Figure 6). Domestic duck Anas platyrhynchos, dorsal vertebrae 2–7 in left lateral view. Note that the two anteriormost vertebrae (D2 and D3) each have a shallow pneumatic fossa penetrated by numerous small foramina.
(What is the relevance of these duck dorsals? You will need to read the discussion in the paper to find out!)
Our choice of publication venue
The world moves fast. It’s strange to think that only eleven years ago my Brachiosaurus revision (Taylor 2009) was in the Journal of Vertebrate Palaeontology, a journal that now feels very retro. Since then, Matt and I have both published several times in PeerJ, which we love. More recently, we’ve been posting preprints of our papers — and indeed I have three papers stalled in peer-review revisions that are all available as preprints (two Taylor and Wedels and a single sole-authored one). But this time we’re pushing on even further into the Shiny Digital Future.
We’ve published at Qeios. (It’s pronounced “chaos”, but the site doesn’t tell you that; I discovered it on Twitter.) If you’ve not heard of it — I was only very vaguely aware of it myself until this evening — it runs on the same model as the better known F1000 Research, with this very important difference: it’s free. Also, it looks rather slicker.
That model is: publish first, then filter. This is the opposite of the traditional scholarly publishing flow where you filter first — by peer reviewers erecting a series of obstacles to getting your work out — and only after negotiating that course to do get to see your work published. At Qeios, you go right ahead and publish: it’s available right off the bat, but clearly marked as awaiting peer-review:
And then it undergoes review. Who reviews it? Anyone! Ideally, of course, people with some expertise in the relevant fields. We can then post any number of revised versions in response to the reviews — each revision having its own DOI and being fixed and permanent.
How will this work out? We don’t know. It is, in part, an experiment. What will make it work — what will impute credibility to our paper — is good, solid reviews. So if you have any relevant expertise, we do invite you to get over there and write a review.
And finally …
Matt noted that I first sent him the link to the Qeios site at 7:44 pm my time. I think that was the first time he’d heard of it. He and I had plenty of back and forth on where to publish this paper before I pushed on and did it at Qeios. And I tweeted that our paper was available for review at 8:44 — one hour exactly after Matt learned that the venue existed. Now here we are at 12:04 my time, three hours and 20 minutes later, and it’s already been viewed 126 times and downloaded 60 times. I think that’s pretty awesome.
References
- Taylor, Michael P. 2009. A re-evaluation of Brachiosaurus altithorax Riggs 1903 (Dinosauria, Sauropoda) and its generic separation from Giraffatitan brancai (Janensch 1914). Journal of Vertebrate Paleontology 29(3):787-806. [PDF]
- Taylor, Michael P., and Mathew J. Wedel. 2021. Why is vertebral pneumaticity in sauropod dinosaurs so variable? Qeios 1G6J3Q. doi: 10.32388/1G6J3Q [PDF]
- Wedel, Mathew J., and Michael P. Taylor 2013b. Caudal pneumaticity and pneumatic hiatuses in the sauropod dinosaurs Giraffatitan and Apatosaurus. PLOS ONE 8(10):e78213. 14 pages. doi: 10.1371/journal.pone.0078213 [PDF]
In my recent visit to the LACM herpetology collection, I was interested to note that almost every croc, lizard, and snake vertebra I saw had a pair of neurovascular foramina on either side of the centrum, in “pleurocoel” position. You can see these in the baby Tomistoma tail, above. Some vertebrae have a big foramen, some have a small foramen, and some have no visible foramen at all. Somehow I’d never noticed this before.
This is particularly interesting in light of the observation from birds that pneumatic diverticula tend to follow nerves and vessels as they spread through the body. Maybe we find pneumatic features where we do in dinosaurs and pterosaurs because that’s where the blood vessels were going in the babies. Also, these neurovascular foramina in extant reptiles are highly variable in size and often asymmetric – sound familiar?
It should. Caudal pneumaticity in the tail of Giraffatitan MB.R.5000. Dark blue vertebrae are pneumatic on both sides, light blue vertebrae only have fossae on the right side. Wedel and Taylor (2013b: Figure 4).
I am starting to wonder if some of the variability we associate with pneumaticity is just the variability of soft tissue, full stop. Or if pneumaticity is variable because it developmentally follows in the footsteps of the blood vessels, which are themselves inherently variable. That seems like a promising line of inquiry. And also something I should have though of a lot sooner.
UPDATE in 2023: A promising line of inquiry indeed! This spawned a paper in 2021, a conference presentation later in 2021, which will become a paper in time, and the tentacles of this idea — that diverticula following blood vessels has a lot of explanatory power — are wound through a LOT of my current and upcoming projects.
Afield in Oklahoma, part 2
June 27, 2018
Ripple rock. Not from the Morrison, but from the overlying Dakota – Lower Cretaceous.
Now this is from the Morrison. My son, London, spotted this tiny tooth of a Jurassic croc while working in the quarry. That’s my thumb and London’s index finger for scale.
London’s index finger again, pointing at a different Morrison tooth. This one’s from a theropod, still exposed in a sandstone block in one of Stovall’s old quarries from the 1930s.
On a completely different hillside, I spotted this skull, of a modern rodent. Vole, maybe? Not my bailiwick, but if you know who this belongs to, let me know in the comments.
Moonrise – and the end of this post. Catch you in the future.
If you are within striking distance of Claremont, come watch me cross the streams of my amateur and professional careers as I talk about the intersection of astronomy and paleontology. And if you can’t make it in person, check out the livestream on the Raymond M. Alf Museum page on Facebook. Show starts Saturday, April 14, at 2:30 PM PDT. https://www.facebook.com/AlfMuseum/
Just got the APP new issue alert and there are three papers that I think readers of this blog will find particularly interesting:
- Ibiricu, L.M., Lamanna, M.C., Martí nez, R.D.F., Casal, G.A., Cerda, I.A., Martí nez, G., and Salgado, L. 2017. A novel form of postcranial skeletal pneumaticity in a sauropod dinosaur: Implications for the paleobiology of Rebbachisauridae. Acta Palaeontologica Polonica 62 (2): 221–236. The latest installment in the ongoing tale of wacky pneumaticity in rebbachisaurids. I reviewed this one, and thought it was solid, interesting work.
- Frederickson, J.A., Cohen, J.E., Hunt, T.C., and Cifelli, R.L. 2017. A new occurrence of Dakotasuchus kingi from the Late Cretaceous of Utah, USA, and the diagnostic utility of postcranial characters in Crocodyliformes. Acta Palaeontologica Polonica 62 (2): 279–286. Near and dear to my heart, as it’s an OMNH specimen written up by a bunch of OMNH folks, including my mentor, Rich Cifelli, and some of his current crop of grad students. I’ve seen this material and it is big and beautiful – so well preserved that it could have come out of a modern croc, if it wasn’t jet black. Note that the Supplementary Online Material includes 3D PDFs of several of the most important elements.
- Cau, A., and Serventi, P. 2017. Origin attachments of the caudofemoralis longus muscle in the Jurassic dinosaur Allosaurus. Acta Palaeontologica Polonica 62 (2): 273-277. A nice addition to the growing corpus of work on tail muscle attachments in dinosaurs.
That’s all for now, just popping in to let people know about these things.
Yes, folks, birds and crocs can pee
January 28, 2016
Stand by . . . grumpy old man routine compiling . . .
So, someone at Sony decided that an Angry Birds movie would be a good idea, about three years after the Angry Birds “having a moment” moment was over. There’s a trailer for it now, and at the end of the trailer, a bird pees for like 17 seconds (which is about 1/7 of my personal record, but whatever).
And now I see these Poindexters all over the internet pushing their glasses up their noses and typing, “But everyone knows that birds don’t pee! They make uric acid instead! That’s the white stuff in ‘bird poop’. Dur-hur-hur-hurrr!” I am reasonably sure these are the same people who harped on the “inaccuracy” of the peeing Postosuchus in Walking With Dinosaurs two decades ago. (Honestly, how I didn’t get this written and posted in our first year of blogging is quite beyond my capacity.)
Congratulations, IFLScientists, on knowing One Fact about nature. Tragically for you, nature knows countless facts, and among them are that birds and crocodilians can pee. And since extant dinosaurs can and do pee, extinct ones probably could as well.
So, you know . . . try to show a little respect.
Now, it is true that crocs (mostly) and birds (always?) release more of their nitrogenous waste as uric acid than as urea. But their bodies produce both compounds. So does yours. We mammals are just shifted waaaay more heavily toward urea than uric acid, and extant archosaurs – and many (but not all) other reptiles to boot – are shifted waaaay more heavily toward uric acid than urea. Alligators also make a crapload of ammonia, but that’s a story for another time.
BUT, crucially, birds and crocs almost always release some clear, watery, urea-containing fluid when they dump the whitish uric acid, as shown in this helpful diagram that I stole from International Cockatiel Resource:
If you’ve never seen this, you’re just not getting to the bird poop fast enough – the urine is drying up before you notice it. Pick up the pace!
Sometimes birds and crocs save up a large quantity of fluid, and then flush everything out of their cloacas and lower intestines in one shot, as shown in the photos dribbled through this post. Which has led to some erroneous reports that ostriches have urinary bladders. They don’t, they just back up lots of urine into their colons. Many birds recapture some water and minerals that way, and thereby concentrate their wastes and save water – basically using the colon as a sort of second-stage kidney (Skadhauge 1976).
Many thanks to Markus Bühler for permission to post his well-timed u-rhea photo.
[UPDATE the next day: To be perfectly clear, all that’s going on here is that the birds and crocs keep their cloacal sphincters closed. The kidneys keep on producing urine and uric acid, and with no way out (closed sphincter) and nowhere else to go (no bladder – although urinary bladders have evolved repeatedly in lizards), the pee backs up into the colon. So if you’re wondering if extinct dinosaurs needed some kind of special adaptation to be able to pee, the answer is no. Peeing is an inherent possibility, and in fact the default setting, for any reptile that can keep its cloaca shut.]
Aaaanyway, all those white urate solids tend to make bird pee more whitish than yellow, as shown in the photos. I have seen a photo of an ostrich making a good solid stream from cloaca to ground that was yellow, but that was years ago and frustratingly I haven’t been able to relocate it. Crocodilians seem to have no problem making a clear, yellowish pee-stream, as you can see in many hilarious YouTube videos of gators peeing on herpetologists and reporters, which I am putting at the bottom of this post so as not to break up the flow of the rant.
You can explore this “secret history” of archosaur pee by entering the appropriate search terms into Google Scholar, where you’ll find papers with titles like:
- “Technique for the collection of clear urine from the Nile crocodile (Crocodylus niloticus)” (Myburgh et al. 2012)
- “Movement of urine in the lower colon and cloaca of ostriches” (Duke et al. 1995)
- “Plasma homeostasis and cloacal urine composition in Crocodylus porosus caught along a salinity gradient” (Grigg 1981)
- “Cloacal absorption of urine in birds” (Skadhauge 1976)
- “The cloacal storage of urine in the rooster” (Skadhauge 1968)
I’ve helpfully highlighted the operative term, to reinforce the main point of the post. Many of these papers are freely available – get the links from the References section below. A few are paywalled – really, Elsevier? $31.50 for a half-century-old paper on chicken pee? – but I’m saving them up, and I’ll be happy to lend a hand to other scholars who want to follow this stream of inquiry. If you’re really into the physiology of birds pooling pee in their poopers, the work of Erik Skadhauge will be a gold mine.
Now, to be fair, I seriously doubt that any bird has ever peed for 17 seconds. But the misinformation abroad on the net seems to be more about whether birds and other archosaurs can pee at all, rather than whether a normal amount of bird pee was exaggerated for comedic effect in the Angry Birds trailer.
In conclusion, birds and crocs can pee. Go tell the world.
And now, those gator peeing videos I promised:
UPDATE
Jan. 30, 2016: I just became aware that I had missed one of the best previous discussions of this topic, with one of the best videos, and the most relevant citations! The post is this one, by Brian Switek, which went up almost two years ago, the video is this excellent shot of an ostrich urinating and then defecating immediately after:
…and the citations are McCarville and Bishop (2002) – an SVP poster about a possible sauropod pee-scour, which is knew about but didn’t mention yet because I was saving it for a post of its own – and Fernandes et al. (2004) on some very convincing trace fossils of dinosaurs peeing on sand, from the Lower Cretaceous of Brazil. In addition to being cogent and well-illustrated, the Fernandes et al. paper has the lovely attribute of being freely available, here.
So, sorry, Brian, that I’d missed your post!
And for everyone else, stand by for another dinosaur pee post soon. And here’s one more video of an ostrich urinating (not pooping as the video title implies). The main event starts about 45 seconds in.
References
- Duke, G.E., Degen, A.A. and Reynhout, J.K., 1995. Movement of urine in the lower colon and cloaca of ostriches. Condor, 97, pp.165-173.
- Fernandes, M., Fernandes, L., Souto, P. 2004. Occurrence of urolites related to dinosaurs in the Lower Cretaceous of the Botucatu Formation, Paraná basin, São Paulo State, Brazil. Revista Brasileira de Paleontologia. 7(2), pp.263-268.
- Grigg, G.C., 1981. Plasma homeostasis and cloacal urine composition in Crocodylus porosus caught along a salinity gradient. Journal of Comparative Physiology, 144(2), pp.261-270.
- McCarville, K., Bishop, G. 2002. To pee or not to pee: evidence for liquid urination in sauropod dinosaurs. In: 62nd Annual Meeting of the Society of Vertebrate Paleontology, Abstract Book. Journal of Vertebrate Paleontology 22(3, Supplement), p. 85A.
- Myburgh, J.G., Huchzermeyer, F.W., Soley, J.T., Booyse, D.G., Groenewald, H.B., Bekker, C., Iguchi, T. and Guillette, L.J., 2012. Technique for the collection of clear urine from the Nile crocodile (Crocodylus niloticus). Journal of the South African Veterinary Association, 83(1), pp.1-7.
- Skadhauge, E., 1968. The cloacal storage of urine in the rooster. Comparative Biochemistry and Physiology, 24(1), pp.7-18.
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Sauropod Vertebra Picture of the Week 