Like other birds, ostriches are fluffy. Too fluffy for some anatomists– so fluffy, it’s hard imagining or estimating what they look like beneath all the feathers. A few years ago, we received an ostrich from a UK farmer. The male bird had been killed by a kick to the neck from another rival, and at the time was supposedly “Britain’s largest ostrich.” As the feathers were valuable to him, the farmer delivered the animal to us whole but plucked. I wanted to dissect it mainly to refresh my memory on ostrich anatomy while developing a biomechanical model of their limbs (see below). Taphonomy expert Jason Moore then buried it for his studies of how bodies decompose.
[Side note: ostriches and other ratites (flightless birds, members of the palaeognath group, whose evolution remains fascinatingly complex) are often brought up as uniquely dinosaur-like. That’s rather misleading; all birds are living dinosaurs, so all birds are descended from an ancestor that was equally ‘dinosaur-like’. What we see of them today is a snapshot that is biased by their recent evolutionary history. During their apparently multiple losses of flight, ratite birds increased in body size and “re-evolved” (or simply enhanced) some traits that were more marked in extinct dinosaurs than in the most recent common ancestor of living birds. Some of those more ‘primitive’ traits may be due to flightlessness, some due to large size, some due to their extreme running specializations; science hasn’t sorted all that out just yet. But the point is, ostriches and other ratites are far from the ancestral form that all birds sprung from, which was probably more like a small, flying tinamou-like animal. Their similarities are due to convergent evolution. And they’re still quite different from something like an “ostrich-mimic” dinosaur- which is a sad misnomer because it’s more that ostriches mimicked (in a naughty teleological sense) ostrich-mimic dinosaurs like Struthiomimus than the other way around; the ornithomimosaurs did it first (Huzzah!). Ratites have just gone back, in some ways but not others (e.g. no long tail or large arms) to a superficially more primitive body form. There have been some wacky ideas to the contrary before, such as the idea that ratites evolved entirely separately from other living birds from different dinosaur stock, but they’re so discredited now by multiple lines of evidence that I won’t glorify them by spending time discussing each. This tangent has gone on too long and must die.]
Anyway, back to the plucked ostrich in question. My first look at it really stunned me. It was a powerful example of just how ‘dinosaurian’ most of the anatomy of living birds is, for reasons noted above. I’d never seen a naked ostrich and now I’ll never look at them the same again. Maybe you won’t, either…
First, some images of the animal once it was brought into our dissection room (which you might recognize from the great Inside Nature’s Giants documentary).
The device near the top of the screen is a digital scale; we were weighing the bird before we cut in…
Close-up view of the hugely muscular legs (each leg is around 25% of the animal’s body weight, and mostly muscle; about 50% more bulky than our legs), and the arms (shown more below).
129 kg weight sans feathers; not bad! That’s about 284 pounds for those folks still mired in the medieval Imperial system of units. 🙂
The swollen, bloody region just below the head (on the left above) is where the mortal blow struck. Ouch!
I love the hands of ratite birds. Yes, those are little claws attached to the three vestigial fingers (thumb/first finger at top, long middle finger, and tiny third finger bound to it). Darren Naish covered some of this in a previous post, and let’s not forget SV-POW’s excellent series of “things to make and do” involving various critters including ostriches.
Ostriches and I go way back. Here I am from my less bald immature postdoctoral days at Stanford University in 2002, dissecting a smaller (female, 65kg) ostrich for some biomechanical modelling (still mostly unpublished; aaargh!).
And yes, I had a third hand back then; later lost during a tragic dissection incident involving a battleaxe and a bottle of tequila. I don’t want to talk about that.
Ostrich packed for transport. Just barely fit in the trunk of my little 1993 Toyota Tercel (R.I.P.)!
Once we complete dissections. we put everything together in some fancy biomechanical computer models (a subject of a future post), resulting in a nice, 3D, poseable, anatomically-realistic model of the entire limb musculature, shown above. This is a right hindlimb in side view, with the individual muscle paths abstracted as red lines. More about this when it is finally published…
This is just a teaser showing off some of the cool external anatomy of ostriches-in-the-buff, and what we’ve done with the anatomical data we’ve gathered. I’ll do a post later showing what’s inside, which is also pretty amazing. Hope you enjoyed it!
Awesome stuff.
Meanwhile, for those who can’t wait for John’s ratite-dissection goodness, there’s always Matt Wedel’s old series of rhea dissection posts: first, second, third.
Whoah! Ostriches have claws? how big are they? looks like a couple of cm, certainly not ‘vestigial’? I thought that of extant birds, only the hoatzin chick had them. Are there any others?
Yes indeed Kattato, all ratites I’ve looked at have nice hand claws. I think some of the other links provided above (by Mike) and in my post show some better pics of the claws in various species (ostrich, rhea; I’ve seen nice claws in emus, cassowary at least). The pic I’ve shown isn’t an ideal image of the claw size- they are sort of long but very thin and somewhat flexible. Some bits of feathers are still hanging on in this picture, obscuring the details of the claws.
They are vestigial relative to earlier dinosaur claws; how vestigial they are relative to living bird claws (e.g. in tinamous, early galloanseriforms etc.) I am not sure of, and doubt anyone has truly studied.
However, I suspect this is a size issue; ratites are big enough that they *can* have noticeable slivers of keratin on the tips of their fingers that don’t wear way/break easily etc. Whereas other birds have little or none in terms of nails/claws; hoatzins just secondarily expanded whatever tissue is hanging around in the embryo to express as claws using the same pathways other birds presumably still have but don’t express much at all. Anyway plenty of cool research could be done on that!
Wonderful. Looking forward to more.
Ostrich wings have been especially vexing to me since visiting Animal Inside Out at the NHM. Are they constructed differently to those of other birds because of their atrophied nature (obvious things such as size and length aside)?
Ooh I still need to see that exhibit, dammit! Gotta get my ass over there.
I don’t know that a good, modern study of ostrich wing anatomy is out there. I’m sure Gadow or someone did some classic stuff though. I know Hans Larsson had a student do a neat study of emu arms a while ago, but AFAIK ostrich arms have not been studied in quantitative detail (except very simple length ratios etc in various comparative studies).
Even less about their function, although they use them a lot in display, possibly during turning, thermoregulation etc.
I stumbled upon this blog in recent days and thought you must have the coolest job in the world. On top of this, you reveal you drove a Toyota Tercel? Honestly, how blessed can one man’s life be?
Hehe, thanks! The job keeps me off the street; that’s probably better for everyone, as I wasn’t too good on the street. 🙂
I’m glad you appreciate the subtle, small glory of Tercels too. I’m not sure I felt blessed at the time (I barely fit in), but I still have fond memories, especially driving across the USA alone, twice (and once during the major blizzard of 1999), in that little car, carrying all my worldly possessions and visiting paleontology museum collections along the way.
Awesome stuff. There’s something rather satisfying about you cramming a female specimen of the largest extant bird into the boot of a car named after the male of a much smaller one.
Regarding bird claws, it’s prob no surprise that Darren Naish has covered this in an excellent series of posts over at Tet Zoo ver 2 – part I, part II, and part III.
Ahh, thanks Mark! I was trying to remember what post(s) I’d seen that detailed the claws, and thought it was TetZoo, but my Google-fu was lacking that day.
Darren Naish put up a photo of living plucked ostriches the other day here.
Ahh, missed that, thanks! Major wow factor!
[…] multicellular organisms. There is a horse skull and a stark white whole skeleton of a young-ish ostrich, which was very nicely mounted although I was caught off guard by the pelvis, which lacked the […]
[…] multicellular organisms. There is a horse skull and a stark white whole skeleton of a young-ish ostrich, which was very nicely mounted although I was caught off guard by the pelvis, which lacked the […]
Wow, ostrich skin is purple, who knew? So is the skin of guinea fowl. Does anyone know the reason for the coloration, and if it appears to serve some purpose, such as sun protection?
I’m guessing that some of that is postmortem change, e.g. blood. My recollection is that the skin in life is more greyish-pink, although that could be wrong.
[…] enough synapsids! Deep inside, every anatomist might secretly be coveting the dinosaurian digestive tract, here represented by a goose’s […]
[…] image of an ostrich foot, check out this plastinated specimen (more pics like it here). We really like ostriches, so we also have an ostrich head and […]
[…] the evolution of bipedal motion along the line of descent to birds. For more ostrich escapades, see this old post. And we’re […]
[…] I confess I used to hate birds. I found them annoying and boring; all that flitting and twitting and pretentious feathers. When I started grad school, I had an open disdain for birds, even moreso than for mammals (OK, except cats). I was a “herp” fan through and through, for most of my life (childhood spent catching anoles in Florida or frogs in Ohio during visits to my grandparents). What won me over was studying birds (and eventually mammals, too) as a scientist, and learning how incredible they are– not just as endpoints in the story of theropod dinosaur evolution, as my thesis focused on, but as amazing animals with spectacular form-function relationships. The Unfeathered Bird is saturated with that amazement, so we’re birds of an unfeather. […]
[…] a-fluttering in your tummy, turn back now! It gets messier. There are tamer pics in my earlier Naked Ostriches post (still, a rating of 6/10 or so for stomach-churning-ness […]
[…] Huge shoutout John Hutchinson. Image from his blog What’s In John’s Freezer? […]