Feathers only rarely fossilize, so the distribution of feathers in dinosaurs is difficult to determine. Sometimes feathers mark the bones, though, and bones do preserve well. Here’s an example: the forearm of a Velociraptor retains an array of small bony bumps evenly spaced along its length. What could they be?
In the photo below is the homologous bone of a turkey vulture, showing similar bumps. They are quill knobs, or places where a ligament anchors the root of a secondary feather directly to the bone. Their presence is an indicator of the presence of a large feather — something more than a little fluffy down — at that location.
(A) Dorsal view of right ulna of Velociraptor IGM 100/981. (B) Detail of red box in (A), with arrows showing six evenly spaced feather quill knobs. In (B), a cast of IGM 100/981 was used. (C) Dorsal view of right ulna of a turkey vulture (Cathartes). (D) Same view of Cathartes as in (C) but with soft tissue dissected to reveal placement of the secondary feathers and greater secondary coverts relative to the quill knobs. (E) Detail of Cathartes, with one quill completely removed to reveal quill knob. (F) Same view as in (E) but with quill reflected to the left to show placement of quill, knob, and follicular ligament. Follicular ligament indicated with arrow.
The top panel of that image is the Velociraptor bone, and some rather more subtle bumps are there, spaced about 4mm apart, suggesting that there were about 14 large feathers hanging from each arm of the dinosaur.
Velociraptors didn’t fly (although if they did, Spielberg would have had real fun with his dinosaur movies), so the unanswered question is what they did with the feathers. Shielding nests? Generating negative lift like a spoiler during running? Knowing what animals do, I’m inclined to suspect they were used for sexual displays … which would imply that they could also have been brightly colored. The special effects people should be more imaginative!
Turner AH, Makovicky PJ, Norell MA (2007) Feather Quill Knobs in the Dinosaur Velociraptor. Science 317(5845):1721.
This is going to have to change our entire view of these dinosaurs – instead of resembling big lizards, we’re going to have to see T. rex and co like ostriches with serious attitude (and teeth, of course). It’s time we had a re-make of Valley of the Gwangi. Squawk!
It’s nice to see how science works. As new information comes along, we radically revise our views of how things we did not or could not see were in the past. Not much faith required for this.
DOES’NT IT TAKE MOR, FAITH TO BEILIVE THAT, SOMETHING CAME FORM NOTHING THAN TO, BELIEF THAT GOD LOVES U!!!!! EVOLUTIN IS DISPROVEN BY, TEH BIBLE IS TRUTH!!!!!!! NO TRANSITIONAL FOSSILS!!!!! SCIENCE IS WRONG YOU CAN’T ,TRUST IT TRUST THE TRUTH!!!!!!!!
Sorry, but when I read Pkps’s thing about not needing faith, I just couldn’t help myself.
So, do you think there is any chance AIG will now pull their “Dinosaur into Birds” video for kids? (WARNING: brain numbing idiocy alert.)
Nah. Didn’t think so.
Those are merely artifacts of god’s phony bone mold.
I saw this article earlier today. Really interesting. We know what they evolved into, but gotta puzzle out what they were first.
Even though they didn’t have any feathered velociraptors on display. I recently got to see some spectacular rare feathered dinosaur fossils at the The Dinosaurs of China exhibit at the Miami Museum of Science. I haven’t been able to look at a bird without thinking dinosaur ever since. So this news just fits right in.
http://www.miamisci.org/www/dinos-of-china.php
There’s an aspect of sexual selection that’s always puzzled me (not having studied as much biology as I should), so let me seize on your suggestion about the possible original function of feathers to ask: Wouldn’t there be a strong selective pressure against organisms prefering mates with otherwise useless paraphernalia?
That is, if the feathers didn’t help the survival of the v-raptor or its offspring, then wouldn’t the extra resources that went into the production of feathers make it less likely that the offspring of the v-raptor who got the hots for feathered v-raptors would survive in competition with the offspring of v-raptors who got the hots for lean, mean, no-frills (or quills) v-raptor (or v-raptor ancestor)?
Same question obviously goes for the peacock (which I’m sure there are many excellent accounts of, which I should but haven’t read). Given that the big old tail of the peacock makes it less likely to survive than a bird with a more sensible tail, isn’t it more likely that a peahen’s offspring will survive if she isn’t attracted to such useless sillinesses as the fancy tail?
Of course, I realize that with evolution by N.S., nature has to take what she can get. So if there is the sexual preference, then that creates a ground for selection. But why isn’t it surprising that there should be these consistent preferences for display paraphernalia, given that it seems that these preferences make it less likely for one’s offspring to survive in competition?
(Sorry for the intro-to-biology-level question, but I’ve been wondering.)
Of course, the fact that research is still on-going and new revelations get press means that we’ll get more fundies arguing “Science doesn’t know anything!” Never mind the fact that new revelations get press goes against their whole “Science is dogma!” argument.
/rant
Would you really expect feathers on a velociraptor? Wouldn’t it be more likely to be some kind of proto-feather thingy, that evolved into feathers on some of velociraptor’s distant cousins? I mean, a feather is a pretty complex, highly adapted structure, optimized for flight. I wouldn’t expect a dinosaur to have anything approaching that.
Then again, the picture of a dinosaur with these display feathers, and maybe sequins, a boa, and high heels, is pretty appealing.
Okay, so osteological traces exist for primary feather insertion. Great.
Can we get over the “oh man, another feathered dinosaur” thing? We’ve been finding feathered dinosaurs for what, a decade now? We already knew from basic phylogenetic inference that feathers were most likely present in all dromeosaurids. Hell, we know they’re basal for all coelurosaurs.
I’m not trying to rain on the “OMGs we have the smoking gun for bird origins” people, but come on, we’ve heard it all before. Over and over and OVER.
Wouldn’t there be a strong selective pressure against organisms prefering mates with otherwise useless paraphernalia?
If I understand it correctly the displays are so they can tell the difference been the males and males other species that kind of look like them. Else you would have velocoraptors getting down with nibbleraptors or what ever was wandering around with them at the time.
If they are anything like modern birds the display feathers would molt off when it was off season for the hens.
Dinosaurs with feathers. Awesome!! I could get into dinosaurs allllll over again now. Neato. :)
Fascinating ideas!
Actually, he had a chance even without flying velociraptors. There were scenes with pterodactyls in the Jurassic Park novel, but they were left out of the movie. And the only reason I know/remember that is that it was a big disappointment at the time.
And they’ve been digging up big ol’ bones for centuries now. There were giant reptiles inhabiting the earth millions of years ago. We get it now. Can we move on?
Physicalist, for what I seem to remember – and I am sure I wil be corrected very fast – that’s exactly the point of such costly displays, a kind of: “look what I can afford to do, how strong I am and the amount of energy I can afford to squander!”
Sexual selection does not work exactly along the lines of natural selection in that it doesn’t always select for the survival of the individual. Still goes for fitness of a kind though…
To Physicalist:
A heavily decorated male (peacock, lyre bird &c.) demonstrates to prospective mates that he is healthy enough to grow his display and fit enough to elude predators even with his heavy display. So he gets the pick of the hens. In addition there are more than enough males to fertilize the females, so it doesn’t matter if a large number get eaten.
The positive feedback aspects of sexual selection are fascinating. My first encounter with this was in one of S. J. Gould’s essays (goodness knows which collection it was in).
…god’s phony bone mold…
Best punk rock band name EVAR.
On the topic of sexual selection:
Also, large, otherwise useless feathers would indicate the male could catch enough food and resist infection enough that the body could waste its resources on the feathers rather than dropping them due to stress.
Physicalist, I think the idea is that the thrivingest specimens are able to afford the ostentatious displays, so the mates choose them. It’s kind of like how driving a BMW makes you less able to afford college for your kids, but is a sign that you have enough wealth to spare that you can waste it that way.
In answer to Physicalist #7:
(I’m sure some actual evolutionary biologists will correct me if I get this wrong)
It is a mistake to assume that every trait “selected” has been done so for the purpose of furthering a species. Evolution can be described as “…species changing gradually over time. Selection being the engine that fuelled these changes.”
A trait may not be a direct result of “selection” but may be a side effect or spandrel of a different trait that resulted in selection.
Conjecture: Feathers in a raptor may have resulted in better high-speed direction control, (or nest sheltering, or thermal control – whatever the feathers may have been used for) and a side-effect may have been males adopting large, bright feathers as part of a sexual selection mechanism.
Thus: Raptors selected for large, healthy feathers would see a direct result of that selection through increased maneuverability. The side effect – bright colouration – may have simply been a “survival neutral” adaptation that was incorporated in sexual selection. (Males able to display their brightly coloured feathers in a mating display were also displaying their “mating fitness” through direct display of the (selected) “large, healthy feathers”
Warning: this post is conjecture based on my guesswork and my opinion, powered by me only…and should be treated accordingly.
Wait a minute…those aren’t quill knobs! Those are DINO-STIGMATA!
Physicalist, I’m of the understanding that sexual selection exists precisely because organisms prefer useless paraphernalia as a shortcut to determining fitness. Peacocks and Irish elk are typical examples of this. If a male peacock can put so much energy into what is essentially a beacon to predators and still survive to reproduce, he must be one helluva tough/quick/sneaky cock. Male Irish elk grew huge antler racks that spanned up to 5 metres. In actuality, they probably served more as anchors to entangle in bushes and generally make life hard. However, surviving with such a handicap makes them that much more attractive to a mate.
It’s like showboating while running for a touchdown, in effect saying, “See, I’m that fast that I can waste energy and still succeed.”
Feathers are not necessarily optimized for flight. Feathers can provide excellent protection against the wet — just ask any duck. They can provide marvelous conservation of body heat and can dump body heat in an emergency much better than fur can. Feathers can provide color and contrast through pigment and structure, and thus can be optimized for display (a peacock) or camouflage (a peahen). (How many ostriches have you seen fly?)
Feathers on a cold blooded predator could easily keep it warmed up so that it could start hunting earlier in the day and keep hunting later in the day, and, suitably colored and shaded, could make it very hard to see as it stalks you.
I may have a poor recollection here but I seem to recall that there is a hypothesis that troodons had feathers.
Thank you all for the instruction; I appreciate it. So the lesson I’m taking away is that the extra cost of developing a display for the females is more than compensated for by enhancing the ability of the female to differentiate the superior stock from the inferior. Makes sense to me (but I welcome correction if I’m still confused).
Thanks again!
Interestingly, I seem to recall a species of fish in which the males had two strategies for succeeding with mates. The first was to be as bright and flashy and tough as possible. Of course, this led to intense competition and fighting between tough males for females.
The other strategy was to be as morphologically as feminine as possible, so that you could sneak in and get the girl while the other jocks were still busy fighting.
Physically, this meant that morphologically, males were either very male or so female that they were hard to distinguish from true females. The males that fell somewhere in the middle tended not to mate successfully.
The easiest example of sexual selection is that the comparative abilities of middle-age male humans to spend outrageous sums of money on diamond jewelry, designer furs, and four-star restaurants does nothing to promote their own survival, but does everything for their ability to get laid. Suposedly, the enticement to the female is that the male is demonstrating sufficient power and resources to raise her children.
Some of Velociraptor’s ancestors were probably capable of flying, so if Velociraptor had non-flight feathers, they would be post-flight feathers (like an ostrich’s or a kiwi’s), rather than proto-feathers (like down on a chick).
Large feathers on a fast-running but non-flying dinosaur might have been very useful in making fast turns while running, without losing speed or putting much stress on ankles and knees. That could be useful in chasing an agile lizard or evading a bigger predator.
People always say that ‘Codswallop’ and ‘What Have You’ and the like are good names for punk bands, but I don’t think they know just how hard it is to really straddle the line between ‘effin Cool’ and ‘WTF’.
I’d imagine that a velociraptor would look a good deal bigger and scarier with a bunch of feathers coming out of it’s (presumably) scrawny arms. Maybe they were used as a defensive technique to make themselves appear larger to bigger carnivores, or as a sort of defense mechanism to obscure their vital organs or create confusing movements.
In any case, I know I’d be pretty scared of a feathered doom vulture lizard
-Boz
Right, pksp. God is just fucking with us. I forgot to get my dose of Mr. Hicks.
By Jove, I think he’s got it!
The sentence above, coined by Physicalist (and abridged by me to make it general), is integral to the understanding of selection. We’ve gotta work this into our arguments with our concern trolls.
In the movie they called them velociraptors but weren’t the ones shown actually the Utah raptors? If i remember correctly the velociraptors were only like 1 and a half feet tall and the Utah raptors were like 6ft. So there’s no reason to go back and add feathers to the movies…not yet anyway.
Physicalist:
“Wouldn’t there be a strong selective pressure against organisms prefering mates with otherwise useless paraphernalia?”
The tail feathers of peacocks are worse than useless, in the jungle they make the males clumsier, slower and easier prey. But this negative effect is more than offset by the positive effects of the sexual selection ensuring the genetic health of the population and that the males that survive to mate are those who are not only healthy and truly free of parasites (which is what that tail truly signifies, it also cannot be faked) but also able to survive despite the handicap.
It has also been suggested, with calculations, that protowings can assist in running uphill or enable things like running up tree trunks. Lift that is insufficient for flying is not necessarily useless. It is also entirely possible that the feathers served multiple roles:
Keeping the animals warm
Protecting them from sunlight and rain
providing lift
acting as sexual selection characteristics
In roughly that order, iow the sexual selection bit came later on. Feathers are prime targets for parasites as animal fur is for things like fleas. So it does not take much of a leap for those animals with the best parasite resistance to have at least the less bedraggled feathers. Evolution can work on surprisingly small differences. All male peacocks may seem equally magnificent to us, but they are not to peahens.
if you try to come up with a good punk band name, it’ll suck. You have to let yourself go, and use the Force, Luke.
True Bob:
Does that mean you wouldn’t buy^H^H^Hdownload an album by “Uppity Atheist Noise Machine”?
But how does any of this explain the Flintstone Flyer?
I think those lines prove that this velociraptor was a cutter.
An “emo kid” if you will.
Blake, if you made that up, you are teh Master. I just mean the name would suck, not necessarily the band.
That’s why I always fly out of bed on cold mornings with my goose-down comforter around me….
Flight feathers are pretty complex, highly adapted structures, optimized for flight. Feathers, however, come in all sorts of sizes, shapes and functions.
Barring some really lucky fossil finds, we’re probably not going to see intermediate forms of feathers because soft tissue is the absolutely rarest kind of fossil there is, but it’s pretty clear that feathers can provide the same protections fur does for mammals.
Given the blurry origin of mammals from probably reptilian ancestry, I’d wonder, personally, if fur is merely a highly specialized feather, or just a different path to the same thing.
I believe that one factor of the ‘useless display’ issue is to show physical characteristics that might indicate the animal in question is more fit for breeding than it’s competitors. It could be health. Genetic fitness. Whatever.
Some species of perch do this. I’m sure there are many others.
Perch sounds about right.
Thanks, Moses.
Only certain sexual ornaments fall under the rubric of the ‘handicap principle’ of sexual selection, such as the long and unwieldy tails of peacocks or widowbirds. Perhaps more germane to this discussion is the broader notion of honest signaling, which posits that variation in external male characteristics (plumage, etc.) is correlated with variation in male quality as a mate. For example, there is some really cool work being done by Geoff Hill, Alex Badyaev, and Kevin McGraw that highlights the connection between male plumage coloration, pigment allocation (esp. carotenoids), and immunocompetence. One of the interesting results from this work is the realization that it isn’t always safe to assume that because an individual devotes energy to one avenue (e.g. feather production) that it necessarily compromises its ability to perform other energetically-costly activities.
We also need to consider that possibility that these putative Velociraptor feathers may serve no adaptive function at all for this genus. Velociraptor may have them simply because their ancestors did. Velociraptor’s ancestor may have been small enough that even protofeathers conferred a thermodynamic advantage and that the feather structure became exapted for flight in other lineages. This of course leads to the whole “when did endothermy evolve?” debate.
As to the multi-gendered fish (male fish with two very different mating strategies and phenotypes) mentioned by Brownian in #26, there are actually several species of fish (not particularly closely related species in many cases) that use such strategies. In one species, the males have three such “genders” – that is, different phenotypes and mating strategies in an evolutionarily stable equilibrium (in their current environmental circumstances). Joan Roughgarden gathers a lot of examples, including some lizards (the subject of her own field research) in her excellent and fascinating (and controversial) book Evolution’s Rainbow.
Physicalist, if you want to learn about sexual selection, I suggest both Roughgarden’s book and the amusing Dr. Tatiana’s Sex Advice to All Creation by Olivia Judson as very absorbing and educational (and in the latter case, downright amusing) reads.
Okay, a number of issues to deal with:
1) No, the dinosaurs in Jurassic Park were not Utahraptor, as that dinosaur had not been discovered when the script had been written, the models made, etc. However, as Utahraptor was described about the time the first JP movie came out, some comments were made about “reality following life.”
In fact, the JP raptors are puny for Utahraptor, and are instead slightly too big for Deinonychus (the first dromaeosaurid known from relatively complete fossils).
2) This is not the first dromaeosaurid for which feathers are known. Microraptor, Sinornithosaurus, Graciliraptor, and others have been found with feather impressions, and quill nodes on the ulna are known from the dromaeosaurid Rahonavis (which, to be fair, was until recently considered a primitive bird rather than an unenlagiine dromaeosaurid).
3) People had recognized that Velociraptor was feathered for the better part of a decade now. Since birds are feathered, primitive dromaeosaurids were feathered, and dinosaurs several branches further from birds (such as oviraptorosaur Caudipteryx) were feathered, than the simplest inference all things being equal was that Velociraptor was feathered.
This is precisely analogous to inferring that Smilodon (the most famous sabre-toothed cat) had fur. No one has ever discovered Smilodon fur, but it is nested among known furry creatures, so to infer that it did NOT have fur requires assuming an evolutionary change for which we don’t have information. Yes, that change is entirely possible, but it isn’t one for which there is evidence.
4) The distribution of feathers is actually pretty well established among theropod dinosaurs. Primitive “fuzz” is known for basal members of Coelurosauria (such as compsognathids and tyrannosauroids). It is only when we reach Maniraptora that we see pinnate (broad) feathers on the arms and tail. It is at Eumaniraptora (birds plus deinonychosaurs (including dromaeosaurids)) that we see long pinnate feathers on the leg, which are lost in the derived bird group Euornithes.
(for those confused by names and relationships, pop over to my classnotes for Dinosaurs: A Natural History; and especially to:
here
and
here.
5) Why did Velociraptor have feathers? Easy: because it inherited them from its ancestors!
The more difficult-to-answer question, of course, is “how did it use them?” And there IS where there are many separate (but not necessarily mutually exclusive) hypotheses:
* display
* brooding
* rapid turning
* use for wing-assisted incline running (especially while juvenile)
* others…
The new information from this specimen is to suggest that even as an adult those feathers were being subjected to loads, which produced the quill nodes.
Hope this helps.
It’s nice to see how science works. As new information comes along, we radically revise our views of how things we did not or could not see were in the past. Not much faith required for this.
Of course if you happen to pop in to the middle of the discussion, after years of increasing evidence that multiple species of dinosaurs had feathers (or may have had feathers) this may seem to be a “radical revision.” You might want to turn on, oh say, the Discovery Channel. Even shows there, which are very watered down for public consumption, have already shown portrayals of juvenile T-Rexes possibly being feathered or “downy.”
This IS how science works, evidence mounts to challenge an existing interpretation of the data, there is skepticism (and in extreme cases attacks and counter-attacks) followed by growing support for a new interpretation of the data and finally by a revision of the consensus.
Unfortunately for you, none of this involves faith, but again, if you aren’t paying attention, and come in half way through the process, it may appear that way. Also, none of this challenges evolutionary theory, in fact it supports it more concisely.
NEAT-O!!
But maybe the bumps are from a life-time of sleeping on a lumpy futon provided by the velociraptor’s human owner. Or maybe the ancient dinosaur breeders liked to tatoo their animals and this left indentations on this creatures arm. Or maybe dinosaurs were infected with a now extinct bone parasite that left bumps at regular intervals. Or maybe this particular velociraptor was owned by a blashpheming human family and God punished them by inflicting it with bumpy bones. Or …
… maybe velociraptors had feathers.
NEAT-O!!!
true, but these feathers had to be substantial enough to need anchoring to the bone. that tells us something. i’m surprised; i would have expected feathers large enough to be useful for temperature control, and possibly for keeping the animal dry, and i would have thought that could be done with skin-anchored feather pens. PZ may be right that they grew larger to serve for sexual selection as well.
The multiple forms of males using different ways of getting mates (known as alternative male strategies)is something known from many types of animals. Bluegill Sunfish are a particularly well-known example which actually have three different strategies.
With regard to Physicalist’s question there are a number of different models for the evolution of traits and preference for those traits through sexual selection. In any one of these models sexual selection for a trait may be opposed by natural selection acting against the trait – however sexual selection can be an enormously powerful evolutionary force in systems where the variation in mating success is high enough.
It is also important to note that traits can also evolve due to sexual selection caused by competition within a sex without a preference being involved at all.
Here is a short summary of different models of sexual selection through mate choice. In all cases I am going to refer to the trait (e.g. peacock’s tail) and the preference – bear in mind that it is entirely possible for the female to have the trait and the male have the preference
Direct Benefits – The trait indicates to the choosing sex something that will directly benefit them if they choose a particular mate (e.g. the male ejaculate in many insects contains a substantial amount of nutrition as well as sperm).
Good Genes/Honest Advertisement – As stated by many posters there is the idea that the trait may be an indication of genetic quality simply because it is costly to produce. The choosing sex gets the advantage of genetically superior offspring. This has been theoretically difficult to model and I am not sure what the current status of the general idea. There are a number of variations on this model involving host/parasite co-evolution and other factors.
Run-away Selection – Proposed by RA Fisher the idea is that the preference and the trait get caught in a positive feedback loop. This idea is popular with theoreticians but has proven to be almost untestable in the real world.
Sensory Bias – The trait evolves to ‘exploit’ a sensory system bias of the choosing sex. This bias has nothing to do with mate choice but is involved in finding food, evading predators, etc.
Species recognition – Mate choice also means mating with individuals of your own species. Traits that allow the choosing sex to avoid mistakes are subject to selection.
Note that these ideas are not mutually exclusive and more than one of them may be involved in a given organism.
Just as a side note, Jurassic Park 4 is in the works and the raptors are rumored to be fully feathered.
#32 In the movie they called them velociraptors but weren’t the ones shown actually the Utah raptors? If i remember correctly the velociraptors were only like 1 and a half feet tall and the Utah raptors were like 6ft. So there’s no reason to go back and add feathers to the movies…not yet anyway.
Actually, the dromeosaurs featured in the films have been somewhere between Velociraptor and Utahraptor in size – more like Deinonychus. I remember seeing the first film as a nerdy kid grown up on dinosaurs and thinking “Hey, that’s a Deinonychus – nothing else!”
@Amenhotep (#1):
and
@pksp (#2):
this is not a radical revision. it’s been the generally accepted idea now for years that velociraptor probably had feathers, due to its strong relationship with microraptor gui and archaeopteryx lithographica. this simply confirms it. greg paul put forth the idea 20 years ago that basically every small theropod had feathers; his books and drawings have featured feathered velociraptors ever since. it is nice to see science works: hypothesize, confirm.
@Curt Cameron (#9):
yes. feathers. not protofeathers. not just down. feathers, probably actual flight feathers, too. because it wasn’t velociraptor’s distant cousins that evolved flight. it was one of velociraptor’s ancestors. archaeopteryx seems to be a basal deinonychosaur. something very much like it would give rise to velociraptor a few million years down the line. it might have even flown. there’s a whole theory that velociraptor actually secondarily lost flight.
@JDP (#11):
yeah, but this one is cool dammit.
@Jefe (#20)
i have an interesting conjecture myself. deinonychosaurs have large (but surprisingly weak and somewhat fragile) claws on their second toes, articulated to be used as precision weapons. the best strategy they probably used was aiming for the soft tissue and major arteries in the neck. that requires speed, surprise, and accuracy — and probably some in-air adjustments. minor flight capability, even if they can’t truly fly, helps with accuracy — meaning fewer broken claws, meaning better chance of survival.
@Bozman (#29):
velociraptor had very large arms, compared to most other dinosaurs.
@Brian W. (#32):
utahraptor speilbergii was discovered after (and named for) the movie. the dinosaurs they showed looked like inflated deinonychuses. they were man sized, not wolf sized, and had much rounder snouts. velociraptor’s is flattened.
@Che (#49):
and carry guns.
Utahraptor, as far as I know, was discovered before or during the filming of the movie (in fact, I think the material was found in the 80’s). It was named after it came out, but it was named in part for John Ostrom, but not I think for good ol’ Steve. There are rumors that it was supposed to be named after him, but unless a paper has come out, that I missed, where it got renamed (always possible), it is U. ostrommaysi.
Fisher’s positive feedback loop is the one that makes most sense to me, even if it is difficult to test.
The driving force behind it is that not only are the genes for ornamentation being passed on, but the genes for desiring that ornamentation as well. So when a female who likes a longer tail mates with a male who has a longer tail, many of their offspring will have genes both for wanting a longer tail and creating one.
The handicap principle (which I believe is attributable to Zahavi) also works in theory, and is also difficult to test.
The overall point, however, is that sexual selection will produce results that in isolation would be scrapped by natural selection. The increased reproductive success makes up for the decreased survival, and then some, in those species we see with prominent sexually selected characteristics.
There’s a very good case to made that many of the differences in appearance between different human races are sexually selected.
In the first Jurassic Park you can see that the velociraptors were originally going to be actual velociraptor sized. The fossil claw Sam Neil carries around is much smaller than the meat hooks on the CG raptors, and when they find the hole in the raptor cage, the opening looks too small for the raptors to fit through. (by the way, I thought JP the movie was more anti-science than the book…and considering we’re talking about Crichton, that’s saying a lot.)
OT- severely
No, I found the Teh best name “Stink Weasel”
using this
maybe the Final Fantasy creators were on to something when they came up with chocobos.
C’mon folks – gaudy plumage is sexually selective because the female (?) raptor is “influenced” by various concepts of male raptor viability, like immunocompetence?
What a bunch of maroons!
Female raptors mated more frequently with nattily-plumaged male raptors for the simple reason that bright male plumage was associated with larger penis size.
And better wristwatches.
Feathers: I get a little impatient with some looking for for JUST this or JUST that or JUST the other purpose. They CAN have multiple purposes. Birds that fly using them very often ALSO have colored and patterned plumage.
Sexual selection aside, from their limb anatomy its clear these critters were great jumpers. I’ve been reading endless dismissals of the possibility of flight, which is quite understandable, but besides cautious speculation that the feathers could have aided their maneuvering WHILE RUNNING, the speculation stops dead right there. Yet that shouldn’t for a moment preclude their aerodynamic utility WHILE AIRBORNE, to be able to maneuver substantially in mid-leap, when those feathers could very well have come in quite handy indeed.
NOT “flying”. Not even “gliding”. Just being able to steer and make significant course and orientation corrections en route to target after springing into the air. There must have been SOME aerodynamic effect involved simply because those feathers are there. Why wouldn’t they have employed them beneficially? If they didn’t, the feathers would have represented a substantial drag, potentially reducing the length of their leaps instead of augmenting them in some way.
It seems to me now that the question to answer is exactly how far and high these guys could have jumped, say, given a running start on a flat surface (neglecting the forelimb feathers, which may well have retained flight-feather morphologies). The derived leap times could conceivably tell us something about how important these feathers might have been in modifying their trajectories, if at all. Maybe something to look into.
Fisher’s positive feedback loop is the one that makes most sense to me, even if it is difficult to test.
And it is possible that all of them are correct, depending on the population being studied. That’s the really neat thing about selection of any type – there are a multitude of possibilities, most of which have been seen in one group or another. It’s another one of the facets of evolution that isn’t adequately expressed in a surface skimming, that there are so many ways it can happen. It’s tempting to say that X is always the mechanism, but of course it’s not that easy. In one species sexual selection via good genes might be the dominant pressure, in another it might be kin selection, in another it might be drift. Life is so cool. Why cheapen it to saying “goddidit” for everything?
This has been my view of raptors for years. Even without flying, they could probably look pretty mean jumping down from a tree. A flap here and there while running for those big jumps. Thankfully they are turkey sized and their claw isn’t used for slashing. I suppose it could pin down small prey, which would kind of suck for small prey.
The real interesting point about this is scientists were wrong. Dead wrong. The view of dinosaurs as reptiles was wrong, dead wrong. They are all far more birdlike than we give them credit for. Avians are dinosaurs and as such obviously survived Noah’s Ark. Why aren’t the creationists jumping on these mistakes?
Because they lose… the view of modern dinosaurs would, when corrected be seen to evolve before everybody’s eyes. Scavenger T-Rex with matted down running after some dead stegosaurus, while a raptor swooped down from the tree to catch a small mammal. — They tried to steal dinosaurs from us… and dinosaurs evolved. So now they lose.
Quoting PZ Myers:
Confirming the presence of feathers in Velociraptor is about as exciting as confirming the presence of Pax6 in Danio albolineatus. Sure, it’s not in the classic model organism D. rerio, but it’s hardly surprising, and it’s not newsworthy. The field of paleontology is already very certain that feathers are a primitive trait for the Maniraptora, and probably the Coelurosauria. This paper would have been perfectly relevant in a journal such as JVP, Palaeontology, or something similar, but it’s certainly not as noteworthy as it’s being touted. Essentially this paper is a response to the exclusivity of the scientists working on the Liaoning specimens; the Flaming Cliffs research group is simply saying “hey guys, we got feathers too!”
Jeepers, who would have known?
Well everyone should have freakin’ known by now that they had feathers, and not damn “protofeathers.” These animals were secondarily flightless, and some more basal relatives, like M. gui could have easily have flown as well, or better than Archaeopteryx. In reality, Archaeopteryx is just another version of these “Raptors”, and its importance is more an accident of History than any thing else.
I am sure some will try and claim “WAIR” and avoid the fact that GP has made another prediction that came true, in a long list of such predictions, but again, those people are just a tad disingenuous anyways,,
Physicalist, think of glossy hair and dancing all night. As I understand it, some sort of dancing is universal in human societies, and serves as a display for the young and sexy.
Feathers may well have developed first for insulation and later for display and flight; but I always think that they are superb for colour changes – seasonal changes, momentary changes caused by rough vs. smooth, delicate gradations or checkering for camouflage, not to mention fluffing onesself up like an offended cat to look bigger. The famous “wings raised” of swans is a threat posture — they are great bullies.
Balancing while in motion, covering young, and scaling heights by running up them could all be aided by feathers.
#CRM-114 #23:
Velociraptors were most likely warm-blooded.
@Brownian #26:
I saw this in a special on Cuttlefish. I believe it was Nature. Two males wrestling over a female while flashing wild colors/patterns. Meanwhile a smaller male adopted the female coloration and mated with the female right under the males’ noses (beaks?).
Another example of multiple male reproductive strategies: In a species of scarab beetle (i dont remember), there are two types of males: Sneakers and fighters. Needless to say, fighters fight each other and the sneakers take advantage of the confusion to get close to the females. It was found, however, that the behavior was linked to horn size (allowing individuals to pursue the strategy that they were best at), but not geneticly (that is, those who were geneticaly disposed to large horns were always fighters) but developmentaly based on how much food they got as larvae. Those who were well-fed and grow larger horns had the genes for fighting behavior activated, and those who were not as well fed became small sneakers, as smaller horns are less of a hinderance in racing other sneakers through the female’s burrow.
I also find it odd that no one has mentioned that, under sexual selection when a single trait is used as a general guide to fitness, there is a strong selection pressure for males who are not as fit to appear to be so, allowing the trait to continue to be selected for.
I also find it odd that no one has mentioned that, under sexual selection when a single trait is used as a general guide to fitness, there is a strong selection pressure for males who are not as fit to appear to be so, allowing the trait to continue to be selected for.
cheaters. do recall how cheating itself is selected against in any given population as well.
btw, if you really want to study multiple reproductive strategies within the same population of critters, fish are the way to go.
There is a species of carribean wrasse that not only shows standard territorial behavior and sneakers, but also piracy – ultra large males taking over a standard male’s nest, then mating with multiple other females who lay eggs in that nest, then leaving the original male to care for both his brood and the pirate’s brood.
what’s even neater is that they are also protandrous hermaphrodites.
now that’s entertainment.
a buddy of mine from grad school was the one who initially discovered the “piracy” mode, and it was immediately published in Nature (not even a single revision!).
fish rule.
especially pirate fish.
I’m sure I could dig up the exact reference if anyone is interested.
I recently read in an Awake magazine that no feathered dinosaurs have ever been found and those that have are fakes!
This must be another fake as the Watchtower Society never ever ever tells fibs.
If you want to learn about sexual selection above the street level, visit Pharyngula.
And it gives satisfaction to see that some of Aves traits evolved earlier and kept in a larger clade. I’m not sure it was mentioned, but another advantage with feathers is protection against predation. Multiple functions there, giving distance to the body, concealing body outline, sacrificial, et cetera.
I presume we have all seen the disappointed cat walking away with just a mouthful of feathers…
If you want to learn about sexual selection above the street level, visit Pharyngula.
And it gives satisfaction to see that some of Aves traits evolved earlier and kept in a larger clade. I’m not sure it was mentioned, but another advantage with feathers is protection against predation. Multiple functions there, giving distance to the body, concealing body outline, sacrificial, et cetera.
I presume we have all seen the disappointed cat walking away with just a mouthful of feathers…
Ichthyic, I’m covering male competition right now in class! Now I have to go find another reference and make them learn a whole other type, thanks a lot….
“Would you really expect feathers on a velociraptor? Wouldn’t it be more likely to be some kind of proto-feather thingy, that evolved into feathers on some of velociraptor’s distant cousins? I mean, a feather is a pretty complex, highly adapted structure, optimized for flight. I wouldn’t expect a dinosaur to have anything approaching that.”
I saw something recently on this, based on a new fossil but damned if I can recall where or the name of the blasted thing at the moment (I’ll post again if I find it). But essentially, it had the birds, troodontids and dromeosaurs all as part of a clade descended from a very small, flying ancestor. If that’s the case, then animals like Velociraptor were secondarily flightless and wouldn’t be evolving feathers but retaining them from its ancestors that had them for flight.
Found it. Interesting stuff at http://www.sciencemag.org/cgi/content/full/317/5843/1378
yup, science is a harsh mistress, Carlie; always fickle, always throwing curves.
since my buddy (Eric Van Den Berghe) first defined the strategy of piracy, I do believe there have been several other examples found, not just in fish, but other taxa as well.
However, I know for a fact that there haven’t been that many papers published on the subject since his was, so it shouldn’t be hard to track down all the papers published on the topic since then.
ah, actually, I have since looked it up, and while he submitted it in 1988, it wasn’t actually published in Nature until 2002 (not surprising):
http://www.nature.com/nature/journal/v334/n6184/abs/334697a0.html
these might also help:
see for example work done by Taborsky (also with wrasses, interestingly):
Taborsky, M. (1994). Sneakers, satellites, and helpers: Parasitic and cooperative behavior in fish reproduction. Advances in the Study of Behavior, 23, 1-101.
Taborsky, M. (2001). The evolution of bourgeois, parasitic, and cooperative reproductive behaviors in fishes. Journal of Heredity, 92, 100-110.
Taborsky, M., Hudde, B., & Wirtz, P. (1987). Reproductive behaviour and ecology of Symphodus (Crenilabrus) ocellatus, a European wrasse with four types of male behaviour, Behaviour, 102, 82-118.
Also, I’m sure you will find Dr. Robert Warner at the University of CA, Santa Barbara to be a fountain of information on this subject.
http://www.lifesci.ucsb.edu/eemb/faculty/warner/index.html
good luck
:)
Just from the forearm. We don’t know if Velociraptor also had wing feathers on the hand the way birds, Microraptor, and Caudipteryx do.
Yes, we would expect real feathers. We just weren’t able to tell if it had retained the expected wing feathers from its ancestors or lost them. Microraptor has modern wing and tail feathers in addition to other types and is more closely related to V. than to the birds; Rahonavis is even closer (which is a recent surprise) and has quill knobs, too; Caudipteryx has modern wing and tail feathers in addition to other types and is less closely related to the birds and V. than the latter two are to each other.
We do expect simpler structures farther away from the birds. And we have found them outside of Maniraptora. That’s what you find, for example, in Sinosauropteryx, which was first described in 1996, and also in the tyrannosauroid Dilong which was described more recently.
Comment 10 is spot-on. :-)
Wing feathers almost certainly didn’t originally have the same use as feathers in general do.
ARGH!
Feathers can only warm something up if it generates heat in reasonable amounts while sitting around. If it does that, it isn’t cold-blooded.
And indeed, there is zero evidence for cold-bloodedness in any dinosaur, and plenty of evidence to the contrary (fast growth rates, [bird-style hyperefficient lungs with] air sacs that invade the bones in saurischians such as V.., and so on).
This isn’t a separate hypothesis, but follows from their position in the tree — they are the closest relatives of the clade (Dromaeosauridae) that includes Velociraptor, Rahonavis, and Microraptor. The most recently published analysis has found the fully feathered Jinfengopteryx to be a troodontid; that’s no surprise.
Well, yeah, but it still wouldn’t look as big as in Jurassic Park…
Stop imagining a lizard!
Imagine a bird with a long tail and without a beak. Something in this direction. (All of these pictures were made when wing feathers on V. were only a reasonable inference rather than a known fact. This is still the case for the wing feathers on the hand that are shown in the first three pictures.)
Sure there is. Assuming that D. or U. had completely lost their feathers is a completely unnecessary and therefore unjustified assumption — keep the tree in mind. Follow the link in comment 73.
We have them! We have them! See Sinosauropteryx and Dilong above — hollow, sometimes branched filaments.
ARGH! The origin of mammals is documented in almost as much detail as a cre_ti_nist could wish for!!! You’re right that the origin of hair isn’t, but the crocs, lizards, and turtles are all closer to the birds than we are, so hairs and feathers are clearly independent developments.
(And “reptile” is a meaningless and misleading term. The mammals are the last remnant of the sister-group of turtles plus lizards [including snakes] & tuataras plus crocodiles plus dinosaurs [including birds].)
Unless the original name already exists, renaming is absolutely forbidden. However, the species name is grammatically incorrect; the correct version is U. ostrommaysorum because it’s named after more than one person.
The “Spielbergraptor” rumors all came too late. Utahraptor was already published.
As far as known, only wing feathers ever produce quill knobs.
Could you be more specific? Who has “avoided the fact that G[regory S. ]P[aul] has made another prediction that came true”? ~:-|
Ladies and gentlemen, a miracle. A sign and wonder.
Just from the forearm. We don’t know if Velociraptor also had wing feathers on the hand the way birds, Microraptor, and Caudipteryx do.
Yes, we would expect real feathers. We just weren’t able to tell if it had retained the expected wing feathers from its ancestors or lost them. Microraptor has modern wing and tail feathers in addition to other types and is more closely related to V. than to the birds; Rahonavis is even closer (which is a recent surprise) and has quill knobs, too; Caudipteryx has modern wing and tail feathers in addition to other types and is less closely related to the birds and V. than the latter two are to each other.
We do expect simpler structures farther away from the birds. And we have found them outside of Maniraptora. That’s what you find, for example, in Sinosauropteryx, which was first described in 1996, and also in the tyrannosauroid Dilong which was described more recently.
Comment 10 is spot-on. :-)
Wing feathers almost certainly didn’t originally have the same use as feathers in general do.
ARGH!
Feathers can only warm something up if it generates heat in reasonable amounts while sitting around. If it does that, it isn’t cold-blooded.
And indeed, there is zero evidence for cold-bloodedness in any dinosaur, and plenty of evidence to the contrary (fast growth rates, [bird-style hyperefficient lungs with] air sacs that invade the bones in saurischians such as V.., and so on).
This isn’t a separate hypothesis, but follows from their position in the tree — they are the closest relatives of the clade (Dromaeosauridae) that includes Velociraptor, Rahonavis, and Microraptor. The most recently published analysis has found the fully feathered Jinfengopteryx to be a troodontid; that’s no surprise.
Well, yeah, but it still wouldn’t look as big as in Jurassic Park…
Stop imagining a lizard!
Imagine a bird with a long tail and without a beak. Something in this direction. (All of these pictures were made when wing feathers on V. were only a reasonable inference rather than a known fact. This is still the case for the wing feathers on the hand that are shown in the first three pictures.)
Sure there is. Assuming that D. or U. had completely lost their feathers is a completely unnecessary and therefore unjustified assumption — keep the tree in mind. Follow the link in comment 73.
We have them! We have them! See Sinosauropteryx and Dilong above — hollow, sometimes branched filaments.
ARGH! The origin of mammals is documented in almost as much detail as a cre_ti_nist could wish for!!! You’re right that the origin of hair isn’t, but the crocs, lizards, and turtles are all closer to the birds than we are, so hairs and feathers are clearly independent developments.
(And “reptile” is a meaningless and misleading term. The mammals are the last remnant of the sister-group of turtles plus lizards [including snakes] & tuataras plus crocodiles plus dinosaurs [including birds].)
Unless the original name already exists, renaming is absolutely forbidden. However, the species name is grammatically incorrect; the correct version is U. ostrommaysorum because it’s named after more than one person.
The “Spielbergraptor” rumors all came too late. Utahraptor was already published.
As far as known, only wing feathers ever produce quill knobs.
Could you be more specific? Who has “avoided the fact that G[regory S. ]P[aul] has made another prediction that came true”? ~:-|
Ladies and gentlemen, a miracle. A sign and wonder.
Ladies and gentlemen, a miracle. A sign and wonder.
yeah, that was a weird thing.
his paper was accepted in 1987 without revision (yes, even then everyone was remarking on that, including his major prof Bob Warner – who was my undergrad advisor at the time), I still have the draft reprints he gave me from back then. Heck I was keeping his place warm while he was off collecting the data for that paper back in 87.
… but I went to actually get the final reference today, and see it as being published in 2002 (has to be the same paper, looking at the abstract and the references)!
what happened in the meantime is a puzzler to me, but I have seen things like that happen before with Journals that have tremendous numbers of submitted articles.
*scratches head*
so, without confirming with my old buddy (who’s now in South America doing work on Cichlids), I’d have to make a correction and say it was ACCEPTED without revision.
OTOH, it has been about a year since I last spoke with him; time for me to send him an email to catch up.
I’ll ask him about it.
David wrote: Unless the original name already exists, renaming is absolutely forbidden.However, the species name is grammatically incorrect; the correct version is U. ostrommaysorum because it’s named after more than one person.
Yep, the species name is grammatically wrong, as it was named for Ostrom and Mays both. And as I’m sure you know, the name has been corrected. But since George couldn’t see fit to do the emending in a valid publication, but rather made the correction in a limited release, self-published, non-reviewed monograph, I’m not actually sure that the official citation is now Utahraptor ostrommaysorum Kirkland, Gaston et Burge 1993 emend Olshevsky, 2000 according to the ICZN, since Olshevsky, 2000 is gray literature at best. I’m not sure what the ICZN feels about this particular case, having not looked into it, but everyone I know still refers to it as U. ostrommaysi (including Norell & Makovicky, 2004, in the second edition of The Dinosauria). *shrug*
Sorry. Unless the name Utahraptor has already been given to something else (which is not the case), renaming Utahraptor is not allowed: valid names stick forever.
You were probably thinking of the phenomenon that genera sometimes get sunk into other genera. For example, Brontosaurus was recognized as a synonym of Apatosaurus; because A. was named first, it wins. This is not technically a renaming. :-] Utahraptor could get sunk this way (though it hasn’t been).
No, no published correction is necessary. The correct version is already correct, no matter if anyone ever uses it. Olshevsky must not even be credited with an emendation. Article 31.1 of the ICZN
And peer-review is not required by the ICZN for anything. Article 8 of the ICZN It will only be required by the PhyloCode. Article 4 of the PhyloCode
Sorry. Unless the name Utahraptor has already been given to something else (which is not the case), renaming Utahraptor is not allowed: valid names stick forever.
You were probably thinking of the phenomenon that genera sometimes get sunk into other genera. For example, Brontosaurus was recognized as a synonym of Apatosaurus; because A. was named first, it wins. This is not technically a renaming. :-] Utahraptor could get sunk this way (though it hasn’t been).
No, no published correction is necessary. The correct version is already correct, no matter if anyone ever uses it. Olshevsky must not even be credited with an emendation. Article 31.1 of the ICZN
And peer-review is not required by the ICZN for anything. Article 8 of the ICZN It will only be required by the PhyloCode. Article 4 of the PhyloCode
(My reply on the nomenclature issues is being held up for moderation because of its three links to the ICZN and the PhyloCode. Both codes are online in their entirety.)
(My reply on the nomenclature issues is being held up for moderation because of its three links to the ICZN and the PhyloCode. Both codes are online in their entirety.)
David,
Roger that. My hard-copy of the ?8th edition or whatever of the code (the ICZN) is at home…so thanks.
David, I think Josh is saying that, once named, a species cannot be renamed unless that name has already been used to describe a different species.
Brownian,
Thanks…I asked the question of David. That was what I thought he meant, but couldn’t tell.
“there is zero evidence for cold-bloodedness in any dinosaur”
David, these are strong words, and they no doubt reflect a strong opinion, but I have to call bullshit. As you well know, there is a huge and contentious literature on this question dating back several decades, with strong and not-so-strong arguments on both sides, and the idea that all dinosaurs were endothermic is by no means accepted by physiologists. And, sorry, but we really have no idea what the lungs of nonavian dinosaurs were like.