Speaker 1: Hi, I'm Aaron Welsh and this is this Podcast Will
Speaker 1: Kill You, and you're listening to the latest episode in
Speaker 1: our mini series of bonus content that we've been releasing
Speaker 1: over the past couple of months. We're nearing the end
Speaker 1: of these bonus episodes for now. We've got just one
Speaker 1: more planned after this, but that doesn't mean that we
Speaker 1: won't come back with more someday. In fact, we'd love
Speaker 1: to do that because these episodes have been so much
Speaker 1: fun and they are such a great way to explore
Speaker 1: even more deeply a topic we covered in our regular
Speaker 1: season episode. For instance, we've been able to dig deeper
Speaker 1: into the world of the epstein bar virus after our
Speaker 1: multiple sclerosis episode, learn about how koalas are impacted by chlamydia,
Speaker 1: understand more about the stigma and discrimination experienced by some
Speaker 1: people living with.
Speaker 2: Hepatitis B, and so much else. In this week's episode,
Speaker 2: we're deviating a bit more from.
Speaker 1: Our regular episode topic than we usually do, but I
Speaker 1: think that makes it all the more exciting because this
Speaker 1: bonus episode covers something that Aaron and I have frequently
Speaker 1: mentioned and expressed our love for on the podcast, but
Speaker 1: have never taken the time to explore in more depth,
Speaker 1: and that is coprolites aka fossilized feces. In our episode
Speaker 1: last week, we talked tapeworms, mostly about the tapeworms that
Speaker 1: commonly infect humans, but those tapeworms only represent a teeny
Speaker 1: tiny part of the puzzle of these parasites. As we mentioned,
Speaker 1: tapeworms are an incredibly ancient and highly diverse group of parasites,
Speaker 1: infecting thousands of animal species all over the globe. We're
Speaker 1: learning more about these amazing creatures all the time, from
Speaker 1: the discovery of new species expanding what we know about
Speaker 1: present day tapeworm ecology, to the identification of tapeworm bits
Speaker 1: in fossils, filling in some of the gaps in our
Speaker 1: knowledge of how these parasites and their hosts have evolved.
Speaker 1: And it's the second part, the fossil part, that I
Speaker 1: really want to focus on for this bonus episode. If
Speaker 1: you listen to our tapeworm episode last week, you may
Speaker 1: remember me mentioning a study from twenty thirteen that found
Speaker 1: tapeworm eggs in fossilized shark feces from two hundred seventy
Speaker 1: million years ago, which is so incredible, not only for
Speaker 1: the simple fact that we can look at and examine
Speaker 1: Pooh from millions of years ago, but also because this
Speaker 1: finding completely revised what we know about the timeline of
Speaker 1: cestode evolution and the history of intestinal parasites. And that's
Speaker 1: typically how coprolites come up on the podcast when we
Speaker 1: trace back how far a human parasite relationship extends, or
Speaker 1: examine how historical distributions of parasites differ from those of today.
Speaker 1: But coprolites are much much more than a tool for
Speaker 1: understanding parasite evolution or host parasite relationships. These magic packages,
Speaker 1: as my guest for this episode has called them, can
Speaker 1: yield incredible amounts of information on the typical diet of
Speaker 1: an extinct animal, the ecological relationships among species, and the
Speaker 1: environmental conditions near the time of fossilization, among other things.
Speaker 1: Although people have been studying copra lights since the first
Speaker 1: decades of the eighteen hundreds, some of the most impactful
Speaker 1: discoveries in this field have been made in just the
Speaker 1: past few decades by doctor Karen Chin, who is one
Speaker 1: of the world's leading experts and copralites. Doctor Chin has
Speaker 1: so graciously agreed to let me ask her all kinds
Speaker 1: of questions about fossilized specs today, and I am incredibly
Speaker 1: excited to dive in. So let's just take a quick
Speaker 1: break here and get to it.
Speaker 3: My name is Karen Chin, and I am a professor
Speaker 3: at the University of Colorado and I'm also curator of
Speaker 3: Paleontology at the cu Or University of Colorado's Museum of
Speaker 3: Natural History. I study ancient ecosystems, and mostly I focus
Speaker 3: on Mesozoic ecosystems, which is the time when the big
Speaker 3: dinosaurs were roaming around.
Speaker 1: Awesome, Thank you so very much for joining me today.
Speaker 1: I have been absolutely fascinated by copralites ever since learning
Speaker 1: about them during my masters and reading about hookworm eggs
Speaker 1: and the peopling of the Americas and all the things
Speaker 1: we can learn from fossilized poop. And I've always wanted
Speaker 1: to dig in a little bit deeper and explore more,
Speaker 1: especially of the non parasite side of things. So I
Speaker 1: am really thrilled for this interview.
Speaker 3: Well, thank you, thank you for inviting me.
Speaker 1: Of course, So could you start us off by defining
Speaker 1: the word copralite, Yes.
Speaker 3: I can. A copralite is fossilized feces. Sometimes people immediately
Speaker 3: think it has to be from a dinosaur, but it
Speaker 3: could be from a fish, or a human or an insect.
Speaker 3: It just means fossilized feces. And there's oh, there's a
Speaker 3: whole variety of them. But I would say that since
Speaker 3: I work on very old fossils over say most of
Speaker 3: them fossils I work on are over sixty six million
Speaker 3: years old. What copralites can be preserved in very what
Speaker 3: I would call young sediments only a few hundred years
Speaker 3: or a few thousand or a million years old, And
Speaker 3: how they are preserved often depends on their age. So
Speaker 3: what the kind of copralites I work on? Are hard?
Speaker 3: They're mineralized, Whereas if you talk to an archaeologist, many
Speaker 3: of the copralites they work on are still they were
Speaker 3: preserved through drying, through desiccation, and if archaeologists rehydrate them,
Speaker 3: they can still have odors. Where most of the material
Speaker 3: WEAK work on is mineralized.
Speaker 2: What do coprolites look like?
Speaker 1: I'm sure there's not a one size fits all answer
Speaker 1: to this question. And so how variable can they be
Speaker 1: in their shape and size?
Speaker 3: They that's a great question. They're highly variable, and their
Speaker 3: variableness often depends on how big they are. So if
Speaker 3: you're talking about little feces from insects or shrimp, they
Speaker 3: often have a very predictable size and shape. But if
Speaker 3: you're talking about feces from say a duckbill dinosaur, often
Speaker 3: they just do not hold their shape, either when they're
Speaker 3: deposited or when they're trampled. And you can see that
Speaker 3: yourself if you go to the zoo and look at
Speaker 3: the elephant dung. One or two of them might be
Speaker 3: have a nice round shape, but many of them are
Speaker 3: just kind of trampled and have no recognizable shape. So
Speaker 3: the shape is usually dependent on the size of the animal,
Speaker 3: and then within that, when feces are first produced, they
Speaker 3: can be oh little teeny pellets, They can be ovoid,
Speaker 3: they can be more like a cowpie, they can be
Speaker 3: really irregular, and this depends again upon the size and
Speaker 3: also upon the diet and the kind of animal that
Speaker 3: produced it.
Speaker 1: Copulates are a type of trace fossil, right, So what
Speaker 1: are some other examples of trace fos foscils and how
Speaker 1: does the information that we can get from these type
Speaker 1: of fossils differ from the info we can glean from
Speaker 1: something like a body fossil for.
Speaker 3: Instance, Yes, that's a great distinction. Body fossils are part
Speaker 3: of what the animal look like or a plant. I
Speaker 3: shouldn't limit it to animals. Of petrified wood is a
Speaker 3: kind of body fossil, because that's part of what constituted
Speaker 3: the structure of the animal. In contrast, trace fossils record
Speaker 3: behavior of different organisms. So tooth marks in say bone,
Speaker 3: or brows in the sediment, or footprints or corpralites, they
Speaker 3: all record some kind of behavior and they tell us
Speaker 3: They provide different perspectives because with body fossils we can
Speaker 3: try to envision what an animal or plant or whatever
Speaker 3: look like, some kind of organism, what they looked like.
Speaker 3: But with trace fossils we can see, oh they burrowed here,
Speaker 3: they burrowed in this manner, what were they doing? What
Speaker 3: did they eat? How did they walk? How fast did
Speaker 3: they run? There's they're different kinds of questions, but they
Speaker 3: enrich our understanding of ancient life.
Speaker 1: Of course, everyone and everything poops, generally speaking, but you
Speaker 1: know what's in that poop can change substantially from day
Speaker 1: to day, and so if a trace fossil like a
Speaker 1: copralite is capturing like a snapshot of an image, a
Speaker 1: snapshot of what that animal ate and that particular day
Speaker 1: and what happened to just be preserved, And so how
Speaker 1: does that affect our interpretation of what we see inside
Speaker 1: that copra late?
Speaker 3: Well, I like that you use the phrase snapshot. We
Speaker 3: like to use that too, because it's just kind of
Speaker 3: a single frame in the whole movie of ancient life,
Speaker 3: and sometimes it can be representative of the past, and
Speaker 3: sometimes maybe it was an aberrant situation. Maybe it would
Speaker 3: be like if you looked at my diet on a
Speaker 3: day that all I wanted to eat was ice cream,
Speaker 3: that might not be relevant for my normal diet.
Speaker 1: So you mentioned, of course that the size of the
Speaker 1: animal and the type of the animal can really affect
Speaker 1: what the copralite looks like simply because of what's in
Speaker 1: the poop.
Speaker 2: And so on.
Speaker 1: But how does that affect how copraltes form? Well, I
Speaker 1: guess my first question is how do they form? And
Speaker 1: then the second sort of add on question is how
Speaker 1: do things like animal diet or the environmental conditions, how
Speaker 1: do those things play a role in whether or not
Speaker 1: that poop becomes fossilized.
Speaker 3: Yes, all those factors are super important. If we go
Speaker 3: back to thinking about archaeological samples that are only maybe
Speaker 3: hundreds or thousands of years old. Those can preserve in
Speaker 3: a very dry environment, say in a cave. But if
Speaker 3: you're talking about older material, the most common method of
Speaker 3: feces being preserved, and it sounds crazy that we could
Speaker 3: actually preserve soft material like feces, but if it becomes mineralized,
Speaker 3: it can preserve it in three dimensions. So the duet
Speaker 3: actually plays a major role in whether ancient feces were
Speaker 3: mineralized or not. Because if you're a carnivore, if you
Speaker 3: feed on vertebrates that have bones or something that has
Speaker 3: only soft tissue, either way that they're is phosphorus in bone.
Speaker 3: There's phosphorus in soft tissue, and that can contribute to
Speaker 3: the mineral called calcium phosphate, and there's a lot of
Speaker 3: calcium around, so that's a little easier to come by,
Speaker 3: but phosphorus is not so easy to come by. So
Speaker 3: if you are a carnivore and have a diet that
Speaker 3: has phosphorus in it, your feces are more likely to
Speaker 3: be preserved if they are deposited in under the right conditions.
Speaker 3: So that means that most of the feces throughout the
Speaker 3: world in museums are mostly from carnivores, which is kind
Speaker 3: of counterintuitive because they're far more herbivores than there are carnivores.
Speaker 3: But herbivore coprolites require an external source of elements that
Speaker 3: can help them be mineralized, so actually herbivore coprolites are
Speaker 3: very very rare.
Speaker 1: And in terms of the environmental conditions at the time,
Speaker 1: or maybe environmental conditions nowadays, are there hot spots that
Speaker 1: we see around the world where there happens to be
Speaker 1: a lot of copralite deposits.
Speaker 3: Yes, indeed, the hot spot would actually be the likelihood
Speaker 3: of whether something is buried or not. And this also
Speaker 3: works in terms of preserving body fossils. Most fossils can
Speaker 3: be more easily preserved if they are rapidly buried, and
Speaker 3: that goes for feces as well, because what happens is
Speaker 3: if the feces are left exposed on the surface, they
Speaker 3: can be subjected to rain, so in any erosion, or
Speaker 3: animals that step on it or feed on it, or
Speaker 3: other things that just decay it, it can be decayed
Speaker 3: by bacteria. If you bury the feces, you can slow
Speaker 3: bacterial decomposition, and if the conditions are right, and we're
Speaker 3: still trying to understand what those conditions are, bacteria can
Speaker 3: actually facilitate mineralization of the soft material. And again this
Speaker 3: seems ironic because bacteria. You usually think of bacteria as
Speaker 3: decaying things, but as bacteria live, they can produce some
Speaker 3: substances or change the micro environment that actually facilitates mineralization.
Speaker 3: And many experiments have been done investigating the role of
Speaker 3: bacteria in mineralization. And it may be that many, maybe
Speaker 3: even most processes of mineralization in place, and I'm talking
Speaker 3: about in sedimentary environment. I'm not talking about volcanics or
Speaker 3: magmas or anything, but just producing chemical minerals in place
Speaker 3: seem to be facilitated by the activity of microbes, especially bacteria.
Speaker 1: And are those bacteria are they environmental bacteria or like
Speaker 1: in the soil, or are they internal bacteria as part
Speaker 1: of like the gut microbiome and shed along with the feces.
Speaker 3: We are still trying to figure out which bacteria can
Speaker 3: do this. The thing about feces is that feces have
Speaker 3: so much so many bacteria in them, but there's lots
Speaker 3: so they can be readily preserved if the conditions are right.
Speaker 3: Which bacteria That's an excellent question. A student that I
Speaker 3: worked with, doctor Joseph Daniel. He once did an experiment
Speaker 3: with me where he buried chunks of bone and then
Speaker 3: dripped a super saturated solution of calcium carbonate over the bone.
Speaker 3: But some of the pieces of bone had been treated
Speaker 3: to reduce the numbers of bacteria. It's hard to get
Speaker 3: rid of everything, but he reduced a lot of them.
Speaker 3: In the chunks of bone where the bacterial populations were reduced,
Speaker 3: there was very little precipitation of the calcium carbonate that
Speaker 3: was percolating through the sand and around the bones.
Speaker 1: Speaking of bacteria, most of the time when we've brought
Speaker 1: up coprolites on the podcast before, it's been in the
Speaker 1: context of parasite eggs, specifically human parasite eggs that have
Speaker 1: been found in certain specimens where and when What does
Speaker 1: that tell us about human evolution or parasite evolution. But
Speaker 1: coprolites can tell us a great deal more about the
Speaker 1: animal that produced that poo than just what parasites they
Speaker 1: may have been infected with. So what are some of
Speaker 1: the other things that we can learn from copralates.
Speaker 3: Yes, we can learn several different things, and it usually
Speaker 3: depends on the kind of preservation of the copralate that
Speaker 3: you're examining. I think the most common source of information
Speaker 3: we look for is what was the animal eating? And
Speaker 3: sometimes we can recognize some very distinctive bits and pieces.
Speaker 3: And you have to kind of think three dimensionally because
Speaker 3: quite often when you're looking at dietary residues in a
Speaker 3: copra light, they've been chomped, they've been digested with gastric juices,
Speaker 3: and then they've probably been changed through geological processes, through
Speaker 3: mineralization or by bacterial decay. So we look for bits
Speaker 3: and pieces that can give us a glimpse into who
Speaker 3: were the victim who was eaten. Sometimes we see pieces
Speaker 3: of bone, sometimes we see pieces of shell, sometimes we
Speaker 3: see lots of leaves, and sometimes those things are very
Speaker 3: very difficult to recognize, but we're getting better and sometimes
Speaker 3: we can see just a little piece of something and say, well,
Speaker 3: that's a piece of bone. In most cases, we assume
Speaker 3: that when we find something in a copral like it
Speaker 3: was eaten, it was food. But sometimes we can also
Speaker 3: see evidence of organisms that were visitors that visited a
Speaker 3: dung pile after it was deposited, and actually one study
Speaker 3: that I worked on with colleagues, we found over one
Speaker 3: hundred and forty I don't know more than that snails
Speaker 3: associated with copra likes. They were preserved in them, on
Speaker 3: top of them, and we examined how complete they were
Speaker 3: and actually found them more Most of them were fairly complete.
Speaker 3: So this suggested that these snails were post depositional visitors
Speaker 3: because snails actually often feed on dung, snails and slugs
Speaker 3: because they like the bacteria in dung, and sometimes when
Speaker 3: people are studying snails, they will put it dung out
Speaker 3: for bait to attract them. So that indicated that in
Speaker 3: this case, even though we found snails in the cobra light,
Speaker 3: they were not necessarily eaten. It's possible that some of
Speaker 3: them were eaten, but it appears that most of them
Speaker 3: visited the dung after it was deposited. So this provides
Speaker 3: another angle of interpreting the ancient environment because this shows
Speaker 3: how waste materials like dung were recycled in ancient environments.
Speaker 3: So we have diet, we have recycling. We can also
Speaker 3: just tell you if something is eaten, it's a contemporary
Speaker 3: of the dinosaurs, so we can learn who was living
Speaker 3: with the dinosaurs, whether or not they were eaten. And finally, well,
Speaker 3: I shouldn't say finally. We're still finding more and more
Speaker 3: about what copraltes can tell us. But i'd say of
Speaker 3: the fourth major category is when we study some copraltes,
Speaker 3: we can learn how it was preserved. And a good
Speaker 3: example of this, the best example that I have worked
Speaker 3: on is when we studied a tronosaur copralite, not t Rex,
Speaker 3: but a smaller, slightly smaller, and older relative, probably ten
Speaker 3: million years older than t Rex, and when we examined
Speaker 3: the copra light we found a mineralized muscle tissue.
Speaker 2: This was just.
Speaker 3: Was so shocking because you'd expect, wait a minute, this
Speaker 3: can't be this went through the dinosaur's gut, and then
Speaker 3: it came out, and you'd think that somewhere along the
Speaker 3: way it was the muscle tissue was either digested or
Speaker 3: else decomposed by bacteria. But what this told us was
Speaker 3: that the gut residence time of the food was rather quick.
Speaker 3: If the food had just sat in the dinosaur's gut
Speaker 3: for a long period of time, it would have been
Speaker 3: more completely broken down. But if it went through relatively quickly,
Speaker 3: you wouldn't necessarily have digestive juices actually attacking every little
Speaker 3: bit of what was eaten. And when I was working
Speaker 3: on this, I found an article that explained that muscle
Speaker 3: tissue has been found in the feces of dogs that
Speaker 3: were fed raw meat. And you figure, if a dog
Speaker 3: has a skull, that's maybe a big dog maybe has
Speaker 3: a canner eleven inch long skull, But a tronosaur could
Speaker 3: have a skull was three feet long, and they could
Speaker 3: not chew like a dog could. They could gulp and swallow,
Speaker 3: So if there was a relatively fast gut residence time,
Speaker 3: all of those bits of food would not necessarily be digested.
Speaker 3: And then once it was deposited, we have to mineralize
Speaker 3: it very quickly before all the bacteria decompose the muscle tissue.
Speaker 3: But again, as we've learned, bacteria can facilitate mineralization, and
Speaker 3: there have been scientists who have taken dead animals like
Speaker 3: dead shrimp and buried them and they have documented mineralization
Speaker 3: of the muscle tissue within weeks. So all of these
Speaker 3: things tell us about a little bit about the digestive track.
Speaker 3: They tell us about the process of mineralization, and that
Speaker 3: was not originally why I wanted to study this Toronto's
Speaker 3: ark for LTE. I wanted to learn about the diet,
Speaker 3: but it provided such an interesting window on other kinds
Speaker 3: of aspects of the fossil record.
Speaker 1: That must have been so thrilling to see that a
Speaker 1: muscle tissue. What an unexpected finding it was.
Speaker 3: It was such a fun study, but it was it
Speaker 3: was challenging because when I first saw it, I thought
Speaker 3: that that doesn't look like plant tissue. Maybe it's muscle tissue. No,
Speaker 3: it can't be. It can't it just can't be. And
Speaker 3: I'd go to bed at night thinking it's not muscle tissue.
Speaker 3: Then I'd wake up in the morning, maybe it could be.
Speaker 3: Then the next day I'd think, no, it's plant tissue,
Speaker 3: and I'd wake up in the morning, No, it could
Speaker 3: be muscle tissue. And so, because I'm not a specialist
Speaker 3: in anatomical tissues, I sought out a colleague at Stanford
Speaker 3: who actually worked on muscle tissues and shared it with him,
Speaker 3: and doctor Rando said, yes, I think this seems to
Speaker 3: be the most likely explanation. So it was. It was
Speaker 3: so surprising, but interestingly as I was making looking at
Speaker 3: the microscope through thin sections of this specimen, I suspected
Speaker 3: that it was muscle tissue. But then one day I
Speaker 3: happened to make some random fin section and could actually
Speaker 3: see the mio fibular striations in skeletal muscle tissue. But
Speaker 3: that was so serendipitous to get just the right angle
Speaker 3: and the right view, and that really helped seal our interpretation.
Speaker 1: And so is that is that one of the major
Speaker 1: ways that you study coprolites is through, you know, take
Speaker 1: making this fossil and cutting tiny little slivers, little sections.
Speaker 2: And putting them on a microscope.
Speaker 1: What are some of the other ways, or if you
Speaker 1: could talk a little bit more about these methods that
Speaker 1: you use to study these culporal lights.
Speaker 3: Yes, I really like making those thin sections, like you explained,
Speaker 3: but it is a destructive process, and before you ever
Speaker 3: do anything like that, you have to first of all
Speaker 3: ask a museum for permission to destructively analyze some of
Speaker 3: a sample. And you often don't necessarily want to do
Speaker 3: too much of this, especially if it's a very unique specimen.
Speaker 3: So that is one way we do microscopy on broken pieces.
Speaker 3: But one thing we are investigating now is looking using
Speaker 3: computed tomography or CT to examine what's inside, and I
Speaker 3: and my students have used X ray computed tomography and
Speaker 3: neutron computed tomography. And one of my colleagues in Europe,
Speaker 3: doctor Martin Farnstrom, has done exceptional work in using synchrotron
Speaker 3: radiation and then he's been able to find really cool
Speaker 3: beetle parts in some of the COPRA lights and other
Speaker 3: things in some of the material he studied, and that
Speaker 3: is really great because it's non destructive. But there's pros
Speaker 3: and cons to both methods. I think sometimes you can
Speaker 3: see more in the thin section, but you're only looking
Speaker 3: at a two dimensional slice and it's destructive. With computed tomography,
Speaker 3: you're seeing three dimensions, but you may not necessarily see
Speaker 3: cellular detail that might be preserved. So well, we're throwing
Speaker 3: is many different techniques at these COPRA lights to learn
Speaker 3: as much as we can. And what we are learning
Speaker 3: these days, I imagine in twenty years people will be
Speaker 3: able to deduce so much more information.
Speaker 1: One of the things that crossed my mind was that
Speaker 1: you're able to tell so much from this copralight, but
Speaker 1: how can you use that information to help you determine
Speaker 1: what animal it might have come from. Is it just
Speaker 1: from the copra light itself or is it also from
Speaker 1: what else you find in the area.
Speaker 3: Yes, this is another time when we use multiple lines
Speaker 3: of evidence. The most important line of evidence is what
Speaker 3: is the age of the sediments. So if I'm looking
Speaker 3: at Cretaceous age sediments, I know that only a certain
Speaker 3: number of animals could have produced it. I won't say
Speaker 3: that was it could have been produced by a wooly
Speaker 3: mammo because they didn't live in the Cretaceous. And then
Speaker 3: you can you can fine tune so that when you
Speaker 3: find a coprali, you're looking at maybe just what are
Speaker 3: the contemporaneous organisms that we find in the sediments of
Speaker 3: the same age. So that is one line of evidence.
Speaker 3: Another line of evidence is the size. If you find
Speaker 3: a really large fecal deposits, you know it wasn't produced
Speaker 3: by a small rodent size mammal. If you find a
Speaker 3: small piece, that's a little more difficult because small pieces
Speaker 3: can come off of a larger fecal mass, and there
Speaker 3: are we know things like deer and rabbits that often
Speaker 3: produce pellet groups. The complete pellet mass is different from
Speaker 3: the mass of one of those little pellets, but size
Speaker 3: is helpful, and then what is inside. If we find
Speaker 3: bone inside, we know we're not looking at a herbivore,
Speaker 3: So you use all of those different line evidence. And
Speaker 3: when we actually studied a very likely t Rex copralite,
Speaker 3: we measured the volume of it and it seemed to
Speaker 3: be about two and a half liters in volume, roughly
Speaker 3: two and a half quartz, and this would be a
Speaker 3: very large fecal mass. So we looked at, well, who
Speaker 3: else lived who lived in those sediments that was a
Speaker 3: carnivore since we knew there was bone in there, and
Speaker 3: we found that many of the animals fell into kind
Speaker 3: of two groups. One were carnivores that were, oh maybe
Speaker 3: a couple hundred pounds roughly, and then there was t
Speaker 3: rex that was much much larger. So between looking at
Speaker 3: the animals that lived at the same time, the fact
Speaker 3: that there was bone in the diet, the size, we
Speaker 3: were pretty confident that this fecal mass was produced by
Speaker 3: t rex. But with a cobra light you often will
Speaker 3: never know. It's quite possible that a large animal that
Speaker 3: was not t rex passed through the area at the time.
Speaker 3: Defecated and did not leave, did not leave any bones behind.
Speaker 3: So always when we talk about who produced the cobra lte,
Speaker 3: I always put probable cobralte from such and such an
Speaker 3: animal in front of it.
Speaker 1: I love the idea of a big dino just passing
Speaker 1: through and just dropping off a copralte and keep going
Speaker 1: and like leaving. People nowadays like what could that have
Speaker 1: been besides t rex? Yes, and so that t rex
Speaker 1: that likely that probable t rex heard is that the
Speaker 1: largest copralite found.
Speaker 3: No. No, We've since found copra lights that are on
Speaker 3: the order of six to eight liters in volume. And
Speaker 3: that's just the ones that I have looked at. I
Speaker 3: know other people keep finding large copralites that may or
Speaker 3: may not be published at this point, but I'd say
Speaker 3: those are among the largest we found.
Speaker 1: So you've talked about two tyrannosaur copralite stories, which I
Speaker 1: think are super fascinating. But I wanted to ask you
Speaker 1: also about another of your groundbreaking findings, which is the
Speaker 1: duckbill corpralites from the two medicine formation. What did you
Speaker 1: learn from these copralites about duckbill diet and maybe dung beetles.
Speaker 3: Yes, this was one of my favorite studies we found. Well,
Speaker 3: I should say it was my boss and mentor, doctor
Speaker 3: Jack Horner, that originally found these weird rocks that had
Speaker 3: lots of plant tissues in them. So for my doctoral dissertation,
Speaker 3: I studied what is the that these are actually copralized
Speaker 3: that like Jack thought they were, And we found good
Speaker 3: evidence that they were from the geological evidence and the contents.
Speaker 3: But another aspect of these coprelizes that was so interesting
Speaker 3: is that many of them had burrows in them. And
Speaker 3: I immediately thought, oh, dung beetles, But then I thought, well,
Speaker 3: I'd never be able to tell a dung beetle burrow
Speaker 3: from a worm borough, so I can't say that these
Speaker 3: are dung beetle borroughs. But when I was studying this project,
Speaker 3: I was contacted by doctor Bruce Gill, who was a
Speaker 3: dung beetle specialist from Canada, and he asked about the
Speaker 3: Burroughs and I just said, well, yeah, there's Burroughs, but
Speaker 3: we can never tell who produced him. And he said, well,
Speaker 3: why don't you send me some photographs and I did,
Speaker 3: and he explained that these burroughs are very distinctive and
Speaker 3: they're in modern environment, we don't have animals that backfill
Speaker 3: sediment with dung to provision these these brood masses for
Speaker 3: the young beetles that will be growing up. And so
Speaker 3: they the dung beetle burrows have very distinctive features, and
Speaker 3: he looked at them and said, those are dune beetle burrows.
Speaker 3: And so that was really that was a really lot
Speaker 3: of fun because it linked the dinosaurs not only with
Speaker 3: the plants they ate, but with the community of recyclers
Speaker 3: we found. We studied these burrows before we found the snails,
Speaker 3: but as we keep learning about these animals that are
Speaker 3: associated with the dung, that actually opens up more and
Speaker 3: more intriguing views of the ancient environment. In fact, one
Speaker 3: of the things not only did we have the dung beetles,
Speaker 3: but these these cobralites were filled with wood, conifer wood.
Speaker 3: And I thought my first publication, I thought, well, if
Speaker 3: these dinosaurs are feeding on conifers, cone bearing trees with
Speaker 3: very short needles, say like junipers or other kinds of
Speaker 3: you know, conifers with very little leaves, of course they're
Speaker 3: going to eat lots of wood. But after further study,
Speaker 3: I realized that the pieces of wood did not correspond
Speaker 3: to the branches that you would expect if they were
Speaker 3: feeding on the leaves. And after more study of the
Speaker 3: cellular structure of the wood, it became evident that the
Speaker 3: dinosaurs had actually ingested rotted wood. And this is it
Speaker 3: seems surprising. A lot of people will say, well, maybe
Speaker 3: it just rotted in. Maybe the structure of the cells
Speaker 3: occurred in the dinosaurs stomach. But it gets a little complicated.
Speaker 3: But I'll just say, in order to get the cell
Speaker 3: structure we found, you have to destroy a component in
Speaker 3: wood called lignin. But to do that it requires oxygen,
Speaker 3: so that cannot happen in a vertebrate gut. So the
Speaker 3: structure that we find in the cobra lights where you
Speaker 3: find the cell structures are broken apart, could only have
Speaker 3: been done by a white rot fungus that would have
Speaker 3: occurred before the dinosaurs ingested it. So then you say, well,
Speaker 3: why were they eating wood? It doesn't make sense. But
Speaker 3: when you decay wood with fungus, you actually make cellulose available,
Speaker 3: so the wood becomes more nutritious. But still it doesn't
Speaker 3: seem why would they eat wood when they could go
Speaker 3: out and eat leaves, Because they're cellulose and leaves, and
Speaker 3: that seems like an easier source of cellulose. But at
Speaker 3: this point in time, our best hypothesis is that the
Speaker 3: dinosaurs were nesting and required sources of protein to help
Speaker 3: support when they laid eggs. They needed to add enough
Speaker 3: protein to those eggs. And if you're a big herbivore,
Speaker 3: probably the best place that you're going to find a
Speaker 3: reliable source of protein that you can actually catch since
Speaker 3: you're not a carnivore, would be something like rotting wood,
Speaker 3: where there'd be termites and crustaceans and all kinds of
Speaker 3: very interesting animals in there. So this built the Again,
Speaker 3: we have the dinosaurs, we have the conifer wood, we
Speaker 3: have the white rot fungi, we have the dung beetle activity,
Speaker 3: we have the snails. And then some colleagues found comparable
Speaker 3: copra lights in southern Utah, and in those copra lights
Speaker 3: there were pieces of crustacean. So this really kind of
Speaker 3: supported the idea that, yeah, these animals, even though they
Speaker 3: were ergivores, did occasionally eat animals, just like most birds
Speaker 3: are tend to be. Even if they're mostly herbivors, they
Speaker 3: will often change their diet when they are getting ready
Speaker 3: to reproduce.
Speaker 2: That is so incredible.
Speaker 1: How you can build this world and paint this picture
Speaker 1: from one like from these these fossils, this fossilized poop.
Speaker 2: It's so beautiful. I love it. I just love that.
Speaker 2: That's amazing.
Speaker 3: I think is pretty cool. Yeah, and oftentimes people will
Speaker 3: think that copra lights can't tell us that much, and
Speaker 3: they're right. Some Copra lights do not tell us that much.
Speaker 3: But some Copra lights, just because of what they're composed
Speaker 3: of and how they're preserved, can provide incredible snapshots that
Speaker 3: give us a view on ancient life.
Speaker 1: We're going to take a quick break here, and when
Speaker 1: we get back, I want to hear all about how
Speaker 1: you were introduced to this incredible world of Copra lights.
Speaker 2: Welcome back everyone.
Speaker 1: I've been really enjoying hearing all about the science of
Speaker 1: Copra lights, But now I want to hear about you.
Speaker 1: How did you become interested in fossils in the first place.
Speaker 1: Were you one of those kids that just loved dinosaurs
Speaker 1: or did that love kind of spark later on.
Speaker 3: I really thought dinosaurs were cool when I was growing up.
Speaker 3: I had, like many young kids, I had a dinosaur book.
Speaker 3: But I never really thought and I never really envisioned
Speaker 3: myself studying dinosaurs. When I grew up, I was interested
Speaker 3: in the modern world. You can walk out your door
Speaker 3: look at plants and animals, and I just thought it
Speaker 3: would be so frustrating to try to study something that
Speaker 3: we could never see again. So I was really quite
Speaker 3: surprised by my reaction. When I started working for doctor
Speaker 3: Jack Horner, I was working as a preparator, cleaning and
Speaker 3: gluing dinosaur bones together, and then I went out and
Speaker 3: the visited their field camps, and I started also researching
Speaker 3: researching paleontology to help write texts for the exhibits. And
Speaker 3: the more I learned about it, the more I was.
Speaker 3: I was hooked. I just I couldn't get enough of it.
Speaker 3: And it was so ironic, because again I never thought
Speaker 3: that I would study something like that, because I really
Speaker 3: thought it would be too frustrating. But instead it just
Speaker 3: different people have different affinities for different subjects, and I
Speaker 3: found that this studying paleontology really fit the way I think.
Speaker 1: And when did coprolates come onto the scene? What was
Speaker 1: the first cope relate that you remember looking at or studying.
Speaker 3: That would be the ones from the to medicine information
Speaker 3: that Jack found. And I never even thought that feces
Speaker 3: could be fossilized. It was and until I was reading
Speaker 3: and writing exhibit text that I learned that people had
Speaker 3: found it. And so I ran to talk to Jack
Speaker 3: and I said, did you know that people have found
Speaker 3: fossilie species? And he said, well, yeah, and I found
Speaker 3: some too, and I was just shocked, and so I said, well,
Speaker 3: at the time, I was working as his histological technician,
Speaker 3: so I was cutting up bone pieces to look at
Speaker 3: the patterns of vascular tissue so he could make inferences
Speaker 3: about physiology and phylogeny of dinosaurs. So I was already
Speaker 3: used to cutting fossil mineralized samples. So I said, well,
Speaker 3: can I cut a piece of this and make a
Speaker 3: thin section? And he gave me permission to do so.
Speaker 3: And when I looked into the microscope they looked at
Speaker 3: that slide, I could see ancient plant cells and it
Speaker 3: just kind of it was a real thrill because I
Speaker 3: realized I was looking at evidence of plant dinosaur interactions,
Speaker 3: and what a cool way to look at how dinosaurs
Speaker 3: interacted with other organisms and environment and That's when I
Speaker 3: got hooked.
Speaker 1: You are an absolute pioneer in the field of copra lights.
Speaker 1: How have you seen this field change over the course
Speaker 1: of your career, either in terms of technology or just
Speaker 1: generally speaking.
Speaker 3: Well, I have found some interesting things. I studied some
Speaker 3: interesting projects in coprolights, but I don't know. I would
Speaker 3: like to point out that people knew about fossilized feces
Speaker 3: before they had ever named dinosaurs, so over one hundred
Speaker 3: years and there have been many, many people who've done
Speaker 3: some really cool work on copra lights. So I don't
Speaker 3: want to claim I'm the only person that studying them.
Speaker 3: Lots of people have studied them. But I will say
Speaker 3: that setting copra lights is not easy. It's really hard,
Speaker 3: and it can be very frustrating because unlike with a bone,
Speaker 3: you can pick up a bone and you say, okay,
Speaker 3: that's a bone and I can figure out who it was,
Speaker 3: or a shell or wood. But when you pick up
Speaker 3: something that you think is a cobra light, first you
Speaker 3: have to say, well, wait a minute, what is the
Speaker 3: evidence that this is fossil pieces? Some of the material
Speaker 3: we look at is and some of it isn't. And
Speaker 3: then you may look at it and find nothing recognizable
Speaker 3: in it, and you may not know who produced it.
Speaker 3: So it's really really challenging. So it helps if you're
Speaker 3: studying some really spectacular examples, and I have been lucky
Speaker 3: to study some of those spectacular examples. But I think
Speaker 3: that these days now people are looking at some of
Speaker 3: the even more difficult ones to study, and they have
Speaker 3: been making conclusions, you know, examining specimens that I may
Speaker 3: not have started to study before, and finding new things,
Speaker 3: just documenting things all over the world. People all over
Speaker 3: the world are studying coprelates, and like I mentioned, my
Speaker 3: colleague is using synchrotron radiation, and people are looking at
Speaker 3: other ways to study them. So I think it's really
Speaker 3: an exciting time for trace fossils because quite often body
Speaker 3: fossils get most of the attention because they tell us
Speaker 3: about great, big or weird animals. But coprelates they're they're interesting,
Speaker 3: but they are more challenging to study, and I'm so
Speaker 3: pleased that more and more people are studying them these days.
Speaker 1: One of the things that I really admire about you
Speaker 1: is just how much outreach and science communication that you do.
Speaker 1: Can you talk about why you feel it is important
Speaker 1: for scientists to connect with the public and share their work.
Speaker 3: I think sometimes people think of science as being a
Speaker 3: black box, that scientists have these answers to things that
Speaker 3: maybe some people may not understand how we came to
Speaker 3: those answers. So I like talking about my work because
Speaker 3: it's easy for people to get excited, especially kids, about dinosaurs,
Speaker 3: and when you throw in something like dinosaur feces, it's
Speaker 3: even a better hook to get people saying, well, that's weird.
Speaker 3: You know, how can you learn about that? So then
Speaker 3: when I talk about my work, they can get an
Speaker 3: idea of how the process of science works and it
Speaker 3: might be more approachable for them. And I think this
Speaker 3: is very important because we all have to We all
Speaker 3: should know more about the way science works and why
Speaker 3: we know what we do, so that when we learn,
Speaker 3: when we get information about changing environments or decisions that
Speaker 3: have to be made that relate to science, we are
Speaker 3: better educated ourselves. So I think it's very important for
Speaker 3: all of us to get an idea of the critical
Speaker 3: thinking that goes into conducting science, and that people understand
Speaker 3: that we're not pulling weird facts out of the air,
Speaker 3: that we do do evidence based research.
Speaker 1: What are some misconceptions about paleontology or paleontologists that the
Speaker 1: general public might have that you would like to correct.
Speaker 3: Oh, I don't know that there's anything really critical. I'd
Speaker 3: say that a common misconception sometimes as people think that
Speaker 3: paleontologists and archaeologists are the same, where paleontologists study ancient organisms,
Speaker 3: non human organisms, and archaeologists study human organisms. But I
Speaker 3: don't even mind if people call me an archaeologist because
Speaker 3: they know we study old things and that's fine. Another
Speaker 3: common misconception and I don't again, I don't think it's
Speaker 3: a bad thing. Is that people often think we get
Speaker 3: to spend all of our time out in the field
Speaker 3: with our pick in hand and finding new stuff, and
Speaker 3: that is so much fun to do. And I should
Speaker 3: say that I have colleagues that can spend months and
Speaker 3: months out of the year, But for the rest of us,
Speaker 3: many of us have to spend more time than we'd
Speaker 3: like to admit sitting in front of a computer trying
Speaker 3: to write up or describe our results. So it can
Speaker 3: sound very glamorous, and some of my colleagues do have
Speaker 3: a very glass lifestyle, but for the rest of us,
Speaker 3: sometimes we get to go out in the field for
Speaker 3: a little while and then spend the rest of the
Speaker 3: time in front of the computers. But again, I don't
Speaker 3: mind these misconceptions because I think I just am happy
Speaker 3: when people are interested in in science.
Speaker 1: Do you feel that graduate students in paleontology are getting
Speaker 1: enough training in communicating their science to the general public.
Speaker 3: I do think I see more and more interest in
Speaker 3: graduate students in learning techniques to communicate the science. I
Speaker 3: really do think that there is a growing awareness of
Speaker 3: how important it is to communicate science, and I'm delighted
Speaker 3: to see many graduate students volunteer to work in museums,
Speaker 3: to do outreach with people, to go out in the community,
Speaker 3: and that's a development that I'm delighted about.
Speaker 1: I've got just one more question for you before I
Speaker 1: let you go. Do you happen to have a favorite
Speaker 1: cobralte pun. I'm sure you've heard many over the years.
Speaker 3: Okay, well, I'll tell you my oldest one. And because
Speaker 3: it's the oldest one, I know some of my friends
Speaker 3: tend to groan every time they hear it, but I'll
Speaker 3: risk that if they happen to hearest. Cobra lights are
Speaker 3: very challenging to study, as I mentioned, and because you
Speaker 3: often do not know, first of all, if it's a
Speaker 3: copralte or who produced it. So I often like to
Speaker 3: tell people that my work is challenging because when I
Speaker 3: study a copralte, I may not know who done it.
Speaker 1: Thank you so much for joining me today, doctor Chin.
Speaker 1: Coprolites are even cooler than I expected them to be,
Speaker 1: and I had some pretty high expectations. And I am
Speaker 1: so excited to do some more reading on the amazing
Speaker 1: world of fossilized feces. And if you too would like
Speaker 1: to learn more about the who, the what, the how
Speaker 1: and the why of copralits, check out the post for
Speaker 1: this episode on our website, This podcast will Kill You
Speaker 1: dot com, where I'll link to a few papers by
Speaker 1: doctor Chin. Also on our website are the sources for
Speaker 1: all of our episodes, transcripts, Quarantini and Placebrita recipes, our bookshop,
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Speaker 1: thank you to you listeners. I hope you enjoyed this
Speaker 1: deep dive into Dino poop, and especial thank you, as
Speaker 1: always to our wonderful, generous patrons.
Speaker 2: We appreciate you so much.
Speaker 1: We've got a brand new episode on a brand new
Speaker 1: topic coming out next week, so until then, keep washing
Speaker 1: those hands.