© 2006 All Rights Reserved. Do not distribute or repurpose this work without written permission from the copyright holder(s).
Printed from https://www.damninteresting.com/curio/the-stinkbird-enigma/
In South America, in the swamps of the Amazon and Orinoco rivers, lives a very unusual bird.
The hoatzin is a pheasant-sized enigma. The official national bird of Guyana, the hoatzin has defied attempts of ornithologists to place it in its proper place among the families of birds. No matter where it is placed, the hoatzin simply does not appear to fit. While bearing superficial resemblance to several other bird species, the hoatzin has many peculiarities that set it apart from the rest. These oddities include some very primitive traits not seen in most birds since the Jurassic period, coexisting with characteristics which are otherwise unheard of among birds.
The first distinctive peculiarity of the hoatzin can be seen most easily on its chicks. They have two claws on each wing, which they use for clambering about the trees. Adults retain the claws, though they do not use them. Few other modern birds have such a thing. However the fossil record shows that several prehistoric birds had such claws, including the earliest and most famous of the ancient birds – Archaeopteryx.
The second peculiarity of the hoatzin has earned it one of its nicknames – the stinkbird. The bird has a strong, unpleasant, manure-like smell, which serves to drive off predators, including humans. Despite their resemblance to game birds and their slow, awkward flight, the hoatzin remains largely unmolested because it makes extremely unappetizing eating. Only during times of famine will locals consider hunting it for food, and even then reluctantly. The source of the off-putting aroma is a feature unique among birds: the hoatzin has evolved foregut fermentation to extract nourishment from leaves.
Foregut fermentation is seen frequently in larger mammals. Cows, sloths, kangaroos, and others have all developed foregut fermentation as a way to extract maximum nutrition from the relatively poor food value of leaves and grasses. Bacteria in the upper part of the digestive tract help to break down cell walls, and the resultant cud is then reprocessed to extract more nutrients. How the hoatzin came to develop it is a mystery. Despite the abundance of leaves in the tropics, no other bird has any kind of foregut fermentation. Indeed, the scientists studying the hoatzin seem amazed that the bird manages its digestive feat with such a small space to work in. Cows stomachs, after all, are huge.
Today, the ornithological consensus is that the hoatzin is the last surviving species of a genetic line that branched off from the rest of the birds 64 million years ago. Whether it’s the most primitive of birds or the most modern, the hoatzin has little to worry about as it feeds its young on cud and merrily emanates its perfume of fermenting foliage. Why should it change, when what it has works so effectively? The odd collection of traits makes the stinkbird a highly efficient eating machine and very unappetizing prey, which is all that matters when the game is survival.
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first
Cool. Another interesting but obscure fact that I can use to dazzle students!!!.
Am I the only one that read the headline as “The Stinkbird Enema”?
Rex: yes.
Cynthia: You’re amazing. Yet another Damn Interesting story.
I wonder if a stinkbird ever met a platypus.
Does this mean D.I. has gone to the birds?!
hammydude said: “first”
And what did you win? :-/ Troll somewhere else.
Marius said: “I wonder if a stinkbird ever met a platypus.”
If they mate would you get a stinkypus?
RichVR said: “If they mate would you get a stinkypus?”
There’s enough of those already…
Very interesting. All new to me.
Awesome article Cynthia, very interesting. And a quite beautiful creature, even if it is pungent.
I saw many of these on a recent trip. I didn’t smell a thing.
“No matter where it is placed, the hoatzin simply does not appear to fit. The hoatzin was given its own family (Opisthocomidae), but since the original designation it has been moved around from being grouped with the game birds (the source of its other name, the Canje pheasant), to grouping it with the cuckoos, to its current, though still speculative placement with the seriema family (most closely related to rails and bustards).”
…geez, with all the problems in the world that NEED to be solved, we’ve got a few bird brain scientists that are squabbling about where to place the Stinkbird on the evolutionary ladder. Must be a government funded project…of course.
what an amazing animal to have as a national bird!
Presumably, some kind of comparative DNA analysis would allow its lineage to be worked out quite quickly, I just don’t fancy being the grad student who has to collect the sample if this thing smells like you say.
another viewpoint said: “…geez, with all the problems in the world that NEED to be solved, we’ve got a few bird brain scientists that are squabbling about where to place the Stinkbird on the evolutionary ladder. Must be a government funded project…of course.”
Let’s breed them and turn them loose in Beirut. Are gas masks still a popular accessory there?
I agree with you. As if there aren’t enough major issues in the world today, lets try classifying a bird. Probably be extinct before they figure it out…
sierra_club_sux said: ”
I agree with you. As if there aren’t enough major issues in the world today, lets try classifying a bird. Probably be extinct before they figure it out…”
Let the biologists do biology. I don’t think that having biologists work on solar/nuclear power or politics, or crime prevention will get anything additional done.
Drakvil said: “Let the biologists do biology. I don’t think that having biologists work on solar/nuclear power or politics, or crime prevention will get anything additional done.”
It might the biologists could find a way to use stinkbirds stink on a nuclear bomb and cost a universal stink bomb that would last for centuries.
I concur with Drakvil. Let the biologists do their work. For the rest of you, there are enough mad scientists trying to blow up this planet already.
Love that evolutionary drivel. If evolution wants everything to live so badly, why no unlimited life spans? Twist that one, Darwinheads.
Shandooga said: “Love that evolutionary drivel. If evolution wants everything to live so badly, why no unlimited life spans? Twist that one, Darwinheads.”
Twist what?
It is you who is twisting the idea in your head. There is no *want* to evolution. That’s purely closed minded drivel.
A species can not evolve without propogation – creatures do not randomly sprout new traits throughout their life. Any creature that hoardes its DNA to itself isn’t contributing to evolution in the slightest. Extended lifespans long past offspring bearing age have little evolutionary advantage. Once an offspring has aged to the point that it begins to breed, there is little advantage to having the original parent present in the mix – its DNA is present in its offspring(s). The younger generations will be healthier out of the simple reality that living organisms wear down over time.
Contrary to your ridiculously simplistic view – species that “live fast and hard” and “breed like rabbits” have the greatest evolutionary advantage. Such species are capable of quick recovery from inclement conditions (disease, famine, etc) due to their short breeding cycles. And they are also capable of rapid spread of advantageous diversification in their genome (“evolving” if you need it spelled out) by means of high rates of propogation. Yet a species that is a quick breeder will rapidly overload their ecosystem – unless they have short lifespans. Be that shortness from physical frailty or high predatation – it matters not.
Sorry Shandooga, but if evolution “wants” anything (as flawed as that idea is), it would want a creature with a short lifespan.
Thank you again for rare and refreshing insight… no where else in my reading matierals can I find the word drivel used more than once or the word bustard used anyplace at all..
Another Viewpoint Said: “…geez, with all the problems in the world that NEED to be solved, we’ve got a few bird brain scientists that are squabbling about where to place the Stinkbird on the evolutionary ladder. Must be a government funded project…of course.”
Ehm, what do you suggest we should spend our time and effort on then? Getting rid of famine, AIDS or war? Hmm, yeah, that’ll be worth the effort. Most of those big bad things will come back either way. Simply because a couple thousand years ago, the same rules that went for the rest of nature, went for mankind. We’ve evolved into being greedy bastards. Just like other animals, we want to survive, and therefore we pick on the weak for our own gain.
If there’s anything we should be working on, it’s trying to fundamentally change mankind. And the role it takes on this planet.
Oh dear, I forgot to add my compliments about the article ;)
Fun to see what evolution can come up with.
David Attenborough did some work on these birds in both his ‘Zoo Quest’ series in the 1950s, and also in his later series ‘Life of Birds’. He talked extensively on the bird (indeed, in Zoo Quest it was one of his main reasons for travelling there) and even though he dedicates pages of his book to his experiences with the Hoatzin, nowhere does he mention it’s pungent odour.
Now I’m not calling you out as a liar or anything. It’s very much the contrary, I’ve been reading around and I trust this site with it’s sources.
But it’s a strange thing for David Attenborough not to comment on, isn’t it? Considering he’s covered them in two series now.
They can swim when they’re chicks as well, incidently. Damn Interesting stuff, eh?
Maybe you can only smell them from a certain distance… like the distance from your fork to your mouth ;)
DI article Cynthia. I’ve read about this bird before while reading about species that are hard to classify.
These birds definitely smell, it’s mentioned in most articles about the bird, hence their nickname ‘stinkbird’.
And ChickenHead, I agree with you 100% but we really don’t need to get into evolution debates. Some people make these anti-evolution comments just to create arguments.
another viewpoint said: “”No matter where it is placed, the hoatzin simply does not appear to fit. The hoatzin was given its own family (Opisthocomidae), but since the original designation it has been moved around from being grouped with the game birds (the source of its other name, the Canje pheasant), to grouping it with the cuckoos, to its current, though still speculative placement with the seriema family (most closely related to rails and bustards).”
…geez, with all the problems in the world that NEED to be solved, we’ve got a few bird brain scientists that are squabbling about where to place the Stinkbird on the evolutionary ladder. Must be a government funded project…of course.”
Yes, an end to middle east violence and global warming would fall right into our laps if those damn shiftless ornithologists would just get on the job! Damn them all!
By way of simple crypt,opisthocomodae,and possible designation,”Rail”.connect with ophidian for serpents or snakes(since trains are snakes,as planes are birds)thus the “op”.As to opisto,there is a variety of snake,agkistodon-(-agkisto-opistho)a somewhat loose or displaced link–(maybe a bird that hangs around with snakes)(and “Rail”roads)
Carl Helsing said: “By way of simple crypt,opisthocomodae,and possible designation,”Rail”.connect with ophidian for serpents or snakes(since trains are snakes,as planes are birds)thus the “op”.As to opisto,there is a variety of snake,agkistodon-(-agkisto-opistho)a somewhat loose or displaced link–(maybe a bird that hangs around with snakes)(and “Rail”roads)”
??? Some of you people have no life…
Sylph-DS said: “If there’s anything we should be working on, it’s trying to fundamentally change mankind. And the role it takes on this planet.”
…absolutely! In which case, classifying Stinkbirds would rate…pretty darn low on the list of things-to-do compared to some of the issues you mentioned and not much higher than whale dung.
NOW…it IS interesting that the Stinkbird’s digestive system is intended to promote survival by keeping threatening animals away. So, are we humans that much different with regards to what our digestion systems can and do do?
Where’s my boss when I need him to test this theory? Darn, he’s never there when I need him and always there when I don’t want him. There’s gotta be a Murphy’s Law in there somewhere!
another viewpoint said: “”
…geez, with all the problems in the world that NEED to be solved, we’ve got a few bird brain scientists that are squabbling about where to place the Stinkbird on the evolutionary ladder. Must be a government funded project…of course.”
Well that’s the narrow-mindedness of some sciences– the need of super structured “classification”. As if it means anything – which it doesn’t.
Oh btw, I think I have a cousin that sounds an awful lot like this – a stinkypus, stinkbird…
Thanks for the article
Rex from Ars said: “Am I the only one that read the headline as “The Stinkbird Enema”?”
You sir, have a mind I aspire to.
another viewpoint said: “NOW…it IS interesting that the Stinkbird’s digestive system is intended to promote survival by keeping threatening animals away. So, are we humans that much different with regards to what our digestion systems can and do do? “
As in “Pull my finger?”
another viewpoint said: “…absolutely! In which case, classifying Stinkbirds would rate…pretty darn low on the list of things-to-do compared to some of the issues you mentioned and not much higher than whale dung.
“
Actually, I think, if our role on this planet was to be fundamentally changed (which it won’t, nobody can be arsed to work on it), observing, registering and protecting of all living things on Earth would be a big part of that role. Thus it’d definitly be important to work out what group the Hoatzin goes into.
Shandooga said: “Love that evolutionary drivel. If evolution wants everything to live so badly, why no unlimited life spans? Twist that one, Darwinheads.”
Troll ftw
Shandooga said: “Love that evolutionary drivel. If evolution wants everything to live so badly, why no unlimited life spans? Twist that one, Darwinheads.”
No need, you’ve already done all of the twisting.
Evolution doesn’t “want” anything, it is a blind process where traits that improve survival and breeding success tend to be passed on and increase in a population. Evolution does not have a “goal” to make things live forever either.
The simple problem with evolving “immortality” is that traits which affect an individual after it has finished breeding (and rearing young in species that do that) are not very relevant from an evolutionary perspective. For example, presbyopia is a hardening of the lens in the eye that occurs as you get older, usually after child bearing age in humans. Evolution has almost no way to select against a trait that only appears after the genes have already been passed on to the next generation. It’s simply too late to select against those genes. The cat, as they say, is already out of the bag. This goes for most of the genes that control an organism’s life after childbirth and any rearing of young is complete. Furthermore, evolution may even select for those harmful traits if they help the next generation survive.
Keep in mind that once a creature has bred (and possibly raised its young) if it stayed around it would probably end up in competition with with its young for resources and such. Depending on the number and survival rate of the young that will determine how many breeding cycles are optimal. After that point, the young are more likely to survive if the parent dies off.
Of course, if a parent has a trait that helps its young survive, and that trait is also in the young, then that trait can be selected for in evolution. This means that since the young bear the same genes as the parents, any gene that causes the parents to die off at an optimal time to open up more resources for the young will tend to exist in the young as well. Since those “dying off”-type genes benefit the young they will tend to get passed on.
In addition to all of that, you have to remember that evolution is a juggling act, and there are many forces at play. If a species reproduces too much without earlier generations dying off quickly enough they can end up consuming all of the resources and create a famine for their species. On the other hand, if you have a long-lived population that breeds fairly slowly (usually at a later age) so as not to strip themselves of resources, one disaster could reduce the population to the point where it could not reproduce enough to recover in time. If the population does not quickly return to its previous size (which it couldn’t do if it was a slow-breeding population) then other species will usually take over those resources, and make the maximum sustainable size of the slow-breeding species smaller than it was before. Repeat incidents like that enough times, and the population will become too small to sustain itself, and die off.
All of that means that species that are too long lived with a high breeding rate can starve themselves out, or if they have a slower breeding rate that is optimal for their lifespans, a periodic disaster will favor shorter-lived faster-breeding species instead of a longer-lived slower-breeding species.
If you want the simple version, imagine what the world would be like if nothing died of old age.
In short, all of that means that longevity beyond a certain point is not a helpful survival trait for a species. That’s a large portion of why evolution doesn’t produce “immortal” species.
Just because we generally see dying of old age as a bad thing, does not mean that it’s not a good thing from an evolutionary perspective.
another viewpoint said: “…geez, with all the problems in the world that NEED to be solved, we’ve got a few bird brain scientists that are squabbling about where to place the Stinkbird on the evolutionary ladder. Must be a government funded project…of course.”
Yes! And I hear that many other people are actually doing insignificant things like brushing their teeth and showering instead of working on more important problems, like world peace! ;-P
There are plenty of people in the world, I don’t see a problem with a few of them spending some of their time solving questions like these.
science-writer said: “Presumably, some kind of comparative DNA analysis would allow its lineage to be worked out quite quickly, I just don’t fancy being the grad student who has to collect the sample if this thing smells like you say.”
Well, according to the Wikipedia article linked to above, the recent comparative DNA analyses put it most likely in a new category, Metaves, along with doves, flamingos, and a few other species of birds.
…geez, with all the problems in the world that NEED to be solved, we’ve got a few bird brain scientists that are squabbling about where to place the Stinkbird on the evolutionary ladder. Must be a government funded project…of course.
There are so many people in the world that leaving the ornitothologists to doing what they want to do isn’t hurting anything. The little things are important too, and focusing everyone on one single problem doesn’t get it done any faster. People who are good at solving the big problems will solve them, the others will solve a little problem that may turn out to be a big thing – some of the smallest problems in history have produced some of the best inventions.
I’d love to get one of those fellas on my bird list.
The brilliant thing is that that would cause me to need to visit South America, where I could potentially add hundreds of species to my list.
Excuse the rabid ticker now. ;)
BOO! IT’S AN EVOLUTION ARGUMENT!!!!!!!! AAAAAAAAHHHHH!!!!!!
Honestly, those things jump out at you at the most unexpected times…
People from Guyana are Guyanese not Guayanans.
is this a peacock relitive,thats so cool
aswome!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Most primitive? Not in my book. Not sure about most modern, either.
However, I can easily say that it appears to the best developed for sheer survival.