Ice Age Horses of the American West

good morning everybody can everybody hear me all right my name is Dan Spivak I'm the head of the resource management program here at the Royal Tyrrell Museum and I'd like to welcome you all to the March 22nd edition of the 2018 royal Tarot Museum speaker series today the Royal Tyrrell Museum and is cooperating Society are proud to present Eric Scott Eric is the principal paleontologist at cog stone resource management incorporated an adjunct professor at California State University San Bernardino San Bernardino are an emeritus curator of paleontology at San Bernardino County Museum and a research associate of the Natural History Museum of Los Angeles County mr. Scott is recognized as a specialist in mammalian anatomy his research focuses on the evolution and extinction of plyo place to see megafauna in western North America and globally particularly horses and their relatives his studies include both fieldwork and museum work throughout the American West as well as in Mexico and the afar region of Eastern Africa from which he has just returned today Eric will discuss his recent work on fossil horses specifically at the tule springs site in Southern Nevada and the natural trapped cave in northern Wyoming so without further delay I present you mr. Eric Scott good morning everybody thank you for coming out it's very nice to be here as Dan mentioned I did just get back from East Africa where even in February it was well into the hundreds so I actually prefer the weather that you guys are offering so thank you for calling that in just to go ahead when we talk about I'm gonna I'm gonna focus primarily on horses iceage horses and particularly from my neck of the woods so this seems a little western United States focused it's because that's where I work but it's also because that's where we hear a lot about Western horses because usually when I tell people I study horses from the American West this is the sort of thing that they think about they think about westerns they think about horses as you perceive them in westerns and that's whether it's in movies out of Hollywood or in books out of Canada where apparently you guys also deal with horses but horses in the West actually have a very real role both in the prehistory and in the history of the American West both in the United States and Canada but when I talk about Western horses I usually refer to this animal this is the extinct Western horse the scientific name is Equus occidentalis and it literally translates as Western horse this is a composite skeleton from the Rancho La Brea Tar Pits in Southern California and when I was a teenager who decided he wanted to be a paleontologist I started volunteering at the La Brea Tar Pits and virtually every other animal there was being studied saber-toothed cats dire wolves bison grounds thoughts and so forth but nobody was looking at the horses so I figured I'd better pick an animal and from that point till now I've been studying Ice Age horses and I was lucky to start at the Tar Pits because the horses there are so well represented horses are the second most common herbivore that they have at the La Brea Tar Pits they've got well over 200 individuals of Ice Age horse so it was a great sample to start with it's not sexy though you don't think about those animals when you think about the ice ages you think about these guys when you think about the ice ages and so you'll almost never hear about Ice Age horses and yet you look at ice age assemblages throughout North America horses are pretty much there in all of them whether it's the answer Borrego Desert or whether it's the Great Plains or even up here if you have ice age assemblages they they're usually with horses in them and those horses are usually well represented and that's because horses are a North American phenomenon and their record here goes back over fifty five million years and so they are quite the success story so what we're seeing in the ice ages is the one of the most recent iterations of horses that go back fifty five million years so from the earliest horses used to be called yo hippest then called hi Rocco theory and now the technical name is sipper hippest through mezzo hippest through skaffa hippest through Equus all of these lineages leading up to living Equus all of these organisms evolved in North America and then spread from North America to the rest of the world this comes as a surprise to some people many of you may have grown up with the idea that the Spanish brought horses to North America and that's certainly the idea that I was presented when I was in grade school and even in high school but technically it was an introduction it was a reintroduction horses died out in the new world around 11,000 years ago and then they were reintroduced when the Spanish came back to the new world in historic times how did that happen how did horses get around to the rest of the world because they by themselves have moved out from North America it's pretty much every other continent except Australia and Antarctica well what happens is during ice ages when you have giant glacial sheets covering most of North America and most of northern Asia and most of North Northern Europe all of that ice locks up ocean water and so while you have the ice in the North the sea level goes down and when sea level goes down this space here between Siberia and Alaska becomes dry land and that dry land is referred to as Beringia and during glacial periods when Beringia is exposed you actually had what's been called a land bridge where animals like mammoths and bison can make it from the old world into the new world and animals like horses can make it from the new world into the old world once horses left the new world made it into the the old world they diversified into all the different kinds of horses and horse relatives that we know of today so we have zebras we have horses we have asses all of them in the same genus all of them in the genus Equus all of them related to each other to some degree or another all of them derived from north american ancestors once human is keyed in on horses and got to the point where they could actually develop artwork and paint what they were looking at humans had developed a fascination with horses even though they were an immigrant animal to the old world nevertheless humans were fascinated by them in fact in many cave paintings horses are the most prominent animal featured and so clearly humans were involved with horses they were hunting horses they were fascinated by horses and then about 6,000 years ago something changed in that relationship and this is when we start to see the domestication of horses because horses have certain characteristics that enable them to be amenable to domestication they have a flexible diet and can survive on relatively low quality foodstuffs they have a reasonably fast growth rate you don't want to domesticate something that's going to take 20 years to mature unless it's maybe your kids but we're talking about animals here you need an animal that can breed in captivity or reduce space you need an animal that you can get along with in many cases an animal with a relatively calm demeanor that doesn't get too excitable in most cases and an animal that has a social structure but the one that is willing to accept a new leader a new focus of that social cohesion and when you think about this horses offer all of these and they aren't alone in that if you think about the other animals that humans have domesticated they offer pretty much the same sort of thing except maybe for cats cats I think have actually domesticated us this little guy is not going to accept a social input from anybody else he calls the shots in terms of domestication there a variety of different pathways to domesticating organisms for example the commensal pathway where the two organisms share similar views and when you think about us versus dogs we both have eyes on the front of our heads facing forward we're both relatively prey focused we're hunting organisms and so dogs or wolves and humans share certain goals and so you can see how they can form a partnership where each helps the other moving towards that goal there is the prey pathway which is pretty straight forward one of them wants to eat the other one and then there is what's called the directed pathway where animals are domesticated for a specific purpose I've got a big animal I wanted to move something heavy let's get it to do that somehow and so those are the three basic pathways that have been proposed for domesticating animals if we look at horses and how they fit and clearly a horse is not a predatory animal it's got the eyes located on the side of its head it's a prey animal there was that one incident with those poor orphans but other than that horses are prey animals they don't they don't attack humans and so it's generally thought that the prey pathway is the likely pathway by which horses were first domesticated they were strictly a source of food but what was nice about horses is that you can domesticate them and have a source of food in cold winter conditions because horses are great at surviving in winter conditions if there's snow and ice on the ground they dig through it with their hooves and they get it the food that's trapped below if you've got goats or sheep they'll use their noses to do that and they bloody their noses and they stop digging and then they die cattle won't even dig through the snow with their noses or anything else you have to take care of them and feed them during the winter but horses will survive during the winter and so it's thought the current thinking is that you started to develop that prey pathway in colder winter conditions so that you had an animal that could survive the winter and provide you with a a perpetual source of meat but then at some point something changed and their relationship changed and people started doing this and nobody's quite sure when or why they're still working on that as I'll talk about in a minute but horses were beautifully engineered for this sort of thing more so than cattle or just about any other animal you can name because horses are hindgut digesters hindgut fermenters when you think about cattle they have multiple stomachs they digest their food in their multiple stomachs they they chew cud they do all of that ruminating stuff horses are different they have all of their food digesting in the intestines in the cecum in the back part of the digestive system and it's so heavy and it's so weighting that their backbones are reinforced to hold up those heavy intestines and so they have a very strong very rigid backbone more so than other animals of their same size and as a consequence they were perfectly set up for somebody to jump on their backs and ride and do so relatively comfortable and comfortably and still have the horse able to support you while doing a bunch of running around and so what you had happened was moving from that prey pathway that we just talked about into a commensal pathway so it ceased being a relation strip relationship strictly of I want to eat these guys too we're partners we're doing something together we're both organisms achieve a benefit out of the relationship and that's really rare and domestication we don't see that with virtually any other animal which is why our relationship with horses is so special as to whether where this happened the earliest archaeological evidence we have for domesticated horses is in a site in Kazakhstan called the bowtie site I hope I'm pronouncing that correctly and it's located there and at the bowtie site archeologists have found lots and lots and lots of horse bones horse bones all over the place they have also found teeth that appeared to have had bits wedged up against them there appears to be bit wear on the teeth they've also found ceramics that have mares milk preserved inside the ceramic vessel and that's that's a very strong indicator of being domesticated you don't want to try and milk wild horses but if it's a domestic one and closed in the corral which they also think they had because they've got deep layers of dung that have been pressed down which suggests that the horses were confined in an area in a small area for a prolonged period and so this is the earliest archaeological evidence and I bring this up because last month this paper came up and I don't know how many of you saw this in science magazine but it was a DNA analysis of the horse bones from the bowtie site and while this is one of those slides that you hate because it's got tiny fonts hopefully I can summarize it up there these are all the bowtie horses and then these are Przewalski's horses living Przewalski's horses and they all clumped together and they clump completely separately from this branch of domestic horses including living domestic horses which means the boat eyesight is separate the bowtie horses which appeared to have been domesticated did not lead to living domesticated horses they're a separate domestication event archaeologically there's still the earliest one we know of but those horses did not leave to the domestic horses that we have with us today it's a different domestication event and because the Przewalski's horses clump with this branch and not with this branch that means that these horses which probably everybody in the room has heard are the last wild horses on earth right anybody they aren't they're feral descendants of the horses that were domesticated at bow-tie there are no living wild horses on the planet anymore these were the last ones and they aren't wild they're feral descendants from bow-tie and so that's a major discovery that forces reevaluating a lot of what we thought we knew taxonomically phylogenetically systematically it really changes what we thought we know about horses it also means that we no longer know where precisely horses were domesticated it used to be thought that it was the bowtie region now there are any number of other potential candidates where it might have happened based on the DNA analyses based on where the samples came from based on the the age of the lineages that are uncovered in the DNA analyses so for those of you who are interested in horse archaeology there's a lot to do what we thought we knew as of last month literally February 2018 we no longer know and so it's a brand new avenue for investigation wherever horses were domesticated though once that happened and once that commensal relationship developed things took off and and since then human civilization is built on the backs of horses when you think about it in warfare in commerce and agriculture and transportation horses are there beside us for pretty much the whole run it's even been said that wherever you find the footprint of man and the longest scent from barbarism a civilization we find the hoof print of the horse beside it you can't say that for any other organism not dogs not cattle not anything horses are really why we are here and why we have the civilization that we have today and this might make you think that that means the story of horses is a story of partnerships with humans and in many cases that's correct because horses survived in the old world because of that partnership with humans we just now learned last month that they didn't survive in any other form they didn't survive in the wild state it's only because they were domesticated by humans that we still have those horses and in North America they didn't survive at all as I said they went extinct at the end of the Ice Ages and they left no descendants in the new world until the Spanish brought them back and so you could think that horses and humans that partnership is why we still have horses and that's a perfectly good thing to think just don't think it around zebras because they are not going to agree with you they will scoff and they will say poppycock and Pro Phooey and and piffle but they won't say nay zebras made it all the way to Africa and this is not Africa this is the Jungle Cruise right at Disneyland but it gets the point across they made it all the way to Africa and they didn't just stay on the sidelines and watch what was happening in Africa they took over they became pivotal organisms in African ecosystems you've probably read about the grazing succession in Africa where it is the Zebras who lead into an area and consume the tall dry forage and then it's the wildebeest who come in and then it's the gazelles who come in and after that that is a series of ecosystems and grazing succession that is built around an animal that emigrated into Africa from old world ancestors that is an amazing success story so yes horses true horses are still with us because of domestication but zebras in many cases are doing just fine on their own because of their own native evolved abilities to survive in those harsh environments in terms of domesticated animals there are still many places on the planet where horses and their relatives are essential to maintaining a way of life in more industrial areas as you probably know horses are less essential in terms of work animals we use them more for sports or recreation or adventure or things of that nature but whether we're and sometimes it's ridiculous what we use them for anything that poor animal that's a huge horse - but irrespective of whether we use them for work or play that relationship that we have with horses started with animals that were adapted to harsh winter conditions that is what led to horses being domesticated and that's why we have the relationship that we have with horses today which is in order for that to happen you need horses to be adapted to winter conditions and so you need two things for that to happen the first is horses the second is winter conditions you need winter conditions and you need horses to have enough time to adapt you need snow you need ice you need ice ages and so the ice ages the onset of the ice ages around 2.6 million years ago is what led to these organisms developing and adapting which then led to the relationship that we enjoy with them today and again our civilization a variety of cultures in the world are built on the backs of horses and so when you look at it in that respect Ice Age horses are the most amazing animal you could possibly want to study they out class any other animal you could possibly want to study as a paleontologist forget these guys know who cares they had nothing to do with us it's ice age horses that you want to be looking at so that's where you want your focus and the study of Ice Age horses goes back as of October of this year a hundred and eighty five years and it starts with this tooth and this tooth was found in 1833 it's the first horse tooth that was recognized as an Ice Age horse to anywhere in the Americas and is discovered by this guy while he was sailing around the world on the HMS Beagle discovered in South America found with other Ice Age sloth bones and so on and Darwin was actually perplexed he looked at this and said what is this horse to doing here because at the time nobody knew that horses had evolved in the new world so he found a horse to where it shouldn't be and so he sent it to this guy Richard Owen who is taking his fossils and examining them it was Richard Owen who said clearly this is an Ice Age species of horse he even named it he called it's Equus curved it ends in 1845 and this is the first new world designation of an Ice Age horse species after that most of the fossils that were found consist of similar things it was horse teeth isolated horse teeth found here and there sometimes you might have this impressive fragment with four teeth in it and so you had paleontologists trying to reconstruct ancient environments based on very fragmentary and and not necessarily complete material as a consequence this is the number of names of horse species that are out there and for those of you who know taxonomy you know that there's something called the rule of priority where the first named the the first species name that's named in the literature is the one that has priority look at all these names that a horse person has to deal with it's really frustrating part of the reason we have these names so many of these names is because the first people who were naming these animals were these guys Joseph's flighty Edward drinker cope and often you'll see Marsh and again they were working in the early days of paleontology evolution was not a firmly established theory even the concept of what defines a species was not necessarily well-established and so they're working very much at the beginnings of paleontology on top of that there was some interpersonal relationship issues coat really really didn't care for Marsh very much Marsh was not a big fan of Koch and so the two of them in addition to fighting each other I worked so long on those slides the two of them in addition to fighting each other and actively sabotaging each other they also tried to out-compete one another and so they did this taxonomically you probably are familiar with this with Dinosaurs with the bone Wars but it actually bled over into horses as well where they're trying to name more horse species than the other one it got so bad that lighty finally said to heck with it I'm out I'm gonna go do something else and he left paleontology completely but as a consequence if you look at this list of names those names over a third of all the horse names out there were named by just those three individuals and in most cases based on insufficient material so it's a very frustrating to have to deal with that level of taxonomy when in fact most of those species can't possibly be valid so it's very very frustrating today we have much more complete remains we have complete skeletons and complete bone beds and we have some beautiful skulls and material from all over North America and South America and all over the world really so there's a lot more to work with we also have better techniques where you can look at weather teeth or primitive verses derived whether your foot bones are shorter and fatter or longer and skinnier whether your lower front teeth your lower incisors have these enamel cups in them or whether they're flat and spatula shaped like these these are all characteristics that you can use to discriminate among different kinds of horses and so you can come up with a list of horse species that would actually by looking at body size cheat teeth the the foot bones and the incisor cups you can just come up with a fairly straightforward approach to the number of different species out there and once you've done that which by the way is a smaller list than the one I showed you that the one from the earlier one had over 60 species here you've got many fewer species than that but you can also key these out by age whether they're early Pleistocene Middle Pleistocene or Late Pleistocene and so you're in a position where you can actually start drilling down into what animals were actually out there and to give you an example of this I'd like to look at just a couple these two species and again I'm gonna focus on where your I work in the western United States and I'm gonna get back to this guy Equus occidentalis the Western horse as it's known from the Rancho La Brea Tar Pits and these are sites that have been published and where you can look at the material and it actually does have fossils that meet all the requirements they're the right size they have right anatomy they have all the right bits preserved there are other records of the species but they're frequently based on insufficient materials so these are good records and this is where you can find evidence of Equus occidentalis that's what the skull looks like again that's Rancho La Brea you get to the rest of the western US though and it's a different species something called Beckwith's kata and you can tell these two apart in a variety of ways but one of the easiest ways is again these enamel cups here and the LaBrea horse Equus occidentalis lacks those cups all together and so you can see that difference clearly what's really kind of interesting is if you go back to the Middle Pleistocene it's all Equus kata you have none of these animals with no cups so what you're seeing is either an evolution area speciation event are you seeing an immigration event but at some point between the middle places seen in the late pleistocene at least in the southwest Equus oxidant Equus cotta is replaced by Equus occidentalis which is really interesting when you want to see what's going on evolutionarily with these animals now that was a nice big picture of the western US if you drill down into where I work here's the actual picture these are all sites in the American Southwest which have yielded horse screaming's and if you look at it these are the only ones that actually have yielded remains that are actually diagnostic two species where you've got all the right bits where you know what you're looking at so look at the number of sites out there that don't have those bits where it's a part of a jaw or it's a part of a skull or it's a hind limb bone but you don't have everything you need there's a lot of horses but very few that tell you everything you want to know and so what do you do with it something like this this is a skull that was found on a construction site because that's where a lot of fossils are coming from now in Southern California this is actually what I do for a living I work for a group called cog stone resource management and we go out on construction sites like this one and we do what's called paleontological mitigation and I understand from Dan that that is actually a big thing up here where you are as well but it's basically going out to construction sites that are expected to encounter sediments that might have fossils in them and when those fossils are encountered you excavate them you put jackets on them you dig them out of the ground this is what it normally looks like where you're exposed and it's nice and sunny more recently my company has been working on the LA subway in finding things like this lil baby mammoth in fact there was a story on CBS just this morning about ground sloth bones from the LA subway did anybody see that well look it up when you get home but that's cog stone resource management that's actually my company finding ground sloth bones and we are also finding horse bones in like this this is a gorgeous horse tooth I was very excited about this I danced all afternoon very exciting but it's the same sort of thing that cope and Martian lady were working with it's nice to know that it's a horse it's a big horse it's a beautiful fossil from the subway but it's not terribly informative compare that to this horse skull which is from San Juan this is not from the subway this is from San Juan Capistrano California and because it's relatively complete you can actually do an analysis is this Equus occidentalis which is what you would expect or is it Equus cotta and so what you do is you do you do science you measure it this is a student from Cal State Fullerton named Marie Kuchar who worked with me on this and we measured the skull it's a large horse had fit within the parameters of Equus occidentalis and then what really sold us was the lower jaw which was found with the skull and if you look at those teeth you can see that there are no of the none of those little enamel cups on those teeth so this is Equus occidentalis which is exactly what you would expect but you needed all the right bits there in order to prove that so we can now add a record of Equus occidentalis that still means that the rest of this area the Mojave Desert is wide open and doesn't tell us anything but there is a site up here called tule springs which you may have heard of it's been excavated for well over a century it's outside a beautiful Las Vegas Nevada how many of you have been there oh my gosh you guys are actually racing your hands good for you if I go to Vegas and ask how many of you have been to the Royal Tyrrell Museum I don't think I'm gonna get the same response but anyway next time you go to Vegas take the time to head north and get out of the city proper and this is what it looks like this is the North Las Vegas region this is specifically the Upper Las Vegas wash and all of these sediments here are groundwater discharge deposits that have fossils in them and the fossils are actually relatively abundant and they've been known about for literally decades but it was only over the past maybe 1516 years that sufficient work was done by me and my colleague Kathleen Springer that the significance of the site was recognized and it was formalized when area was designated one of the u.s. new national monuments tule springs Fossil Beds National Monument and so are their horse fossils there yes and a lot of them look like this even cruddy er than that one I showed you from the subway that is what's left of ours two sitting at the surface and that's what a lot of the horse fossils from Las Vegas that have been collected over the past century and more look like so not a lot you can do however that ended in 2012 with these Bureau of Land Management site stewards working under our supervision were in the field to excavate what they thought was going to be a mammoth and we know there's a mammoth there there's a mammoth tooth there there's a mammoth tusk there but as they were digging they also found this and that is a baby horse tooth and it turns out to be a baby horse tooth from a baby horse jaw and then we found the upper part of the skull and so this is actually one of the most complete remains from tule springs it may not look like much but it's got all the right bits including the lower jaw and here you've got you do have those enamel cups and so we can go back here and we can key it out and in terms of large size derived cheek teeth stout meta podía land incisor cups that's Equus cotta and it's the first that specimen cruddy though it is is the first specimen after over a hundred years of digging or work at tule springs that's the first horse that could be identified to species and so when we go back to our map we can now add that in and it's a different species and so if we go back to our big map you can see that there's the San Juan Capistrano find there's the tule springs find and they're fitting the general pattern you're seeing exactly what you think you might want to see and this is important however I would emphasize here we're looking at large horses I've been sticking so far with just the large horses there are other horses out there and if you look at the Thule Springs record this is a toe bone and this is just a graphic plot all of these are small horses these are what's known as stilt legged horses I'll talk about them more in a minute these are more stout lend horses and this phalanx here this toe bone fits right in there with the small stout limbed horses so this is not a big horse it's a little horse but it's got relatively stout limbs we've also got this bone which is a long skinny one unfortunately incomplete but here's your large horses here's your small stout limbed horses here's your small stilt legged horses and this thing plots way way down here so it looks like it's a stilt legged horse which means at tule springs you potentially have three species of horse coexisting maybe not all in the same area but I mean they died in the same area they were fossilized in the same area but not necessarily all living and overlapping maybe they some kept more to the mountains some kept more to the valleys some kept more to the woods what-have-you still you've got them all fossilized in the same area and this is kind of where I'm coming from with my Western us perspective is that we have this many horses out there and so the reason I emphasize that is because more recent studies based on DNA have suggested that maybe that story is incorrect this is actually these are a couple of papers that are looking at DNA and this is actually the current revolution in horse studies it's not so much what the paleontologists are doing it's what DNA analyses are suggesting and so for those of you familiar with DNA I'm sure I'm not telling you anything you don't know but your cells have DNA preserved in them and so fossil organisms have DNA preserved in their cells if that is actually if they're the preservation is sufficiently good and there are two different kinds basically two different kinds of DNA analyses some get DNA out of the mitochondria this is a smaller subset it's inherited from the mothers there's there's less material to work with more recently you have nuclear DNA studies where they're actually getting DNA out of the nucleus and that's providing a somewhat different and hopefully much more complete picture of what's going on in some of these organisms this is actually a tree from a mitochondrial DNA study that was published in 2005 and so what I'd like you to see here is that you've got Przewalski's horses and in 2005 they were still considered wild horses but that's not necessarily pertinent in this case what we see is that they are there in tree a and they're in the middle of all these other domestic horses and this is not news to many people the Przewalski's horses and domestic horses are the same species again the study last month says that there are different lineages but there are different lineages within the same species what you also see in tree a is stuff from Alaska and the Yukon from the Pleistocene which means that the species of domestic horse and the species of Przewalski's horse were also that species was here in North America during the Ice Ages and very closely related are all of these guys down here very very closely related probably the same species now for those of you who are eagle-eyed and looking very carefully what you're also going to notice is all of these from the Yukon and from Alberta it it's all you guys it's you luck so at this point Pacha cells on the back because it is fossils from your backyard that are changing the pictures specifically from Alberta and from the Yukon and the reason that's happening is because of this stuff you've got called permafrost and permafrost is generally permanently frozen sediment and in many cases it's got fossils in it and in some cases it has been mined in other cases it is now no longer permanent because of increasing global warmth and so as this permafrost melts you start to see fossils appearing whether it's melting or I shouldn't say whether it's warming up or whether it's being mined you start to see fossils like this beautiful horse skull in some cases they're even better looking that is a horse limb that still has skin and hair on it from the permafrost again this is from your backyard and when the preservation is that good when this stuff has been frozen for that long you can get DNA out of it now what's interesting again coming back to where I work which is in the western United States primarily in addition to all of these Alaskan and Yukon and Alberta fines there's also this stuff from Wyoming which you don't have permafrost but what you do have is this cave called natural trap cave which is a wonderful it's a fantastic fossil site and that's what it looks like from the inside it is a beautiful cave with a span of 86 feet or 26 meters for you guys and the rest of the world who uses metric that's what happened is during the ice ages animals running along hit that hole and fell and I originally wanted to do an animation but it got way too graphic and pretty gross Oi I got rid of the animation but horses and other animals plummeting 86 feet and going splat is that's how these animals came to be preserved they ended up at the bottom of this cave paleontologists don't like to get to the bottom of the cave that way so what we do is grievant pill down this is actually dr. Julie Meacham she's the lead scientist on this endeavor from Des Moines University of Des Moines and so this is her work and I got to participate as part of this but rappelling down 86 feet is worth it when you find fossils preserved like this it can be 90 95 degrees at the surface you draw and I'm using Fahrenheit sorry I can't do the Celsius but you drop down to the bottom and it's in the mid 30s to 40s it's a pocket of the ice ages that has never warmed up and so kind of like permafrost what you've got is these animals in cool moist conditions and so they're - you still have DNA preserved and so you have fossils like that bone there's a horse hoof there's a horse toe there is a horse tooth beautiful material that still has DNA in it and so many of the fossils were collected and sampled for DNA to determine what was going on these are not the first excavations at natural track cave it was actually excavated in the 1970s this is before DNA analyses got started and so I this up because based on the literature based on those collections it's been suggested that there were three species of extinct horses and natural trap cave using the same fossils it's so been suggested there were four species of extinct horses and it's been suggested that there were five species of extinct horses all using the same fossils different scientists looking at them in different ways and coming up with different conclusions which can be very frustrating fortunately the fossils are preserved in Kansas at this wonderful institution and you have short stout and long skinny foot bones and so if you plot them out here's your stout and small here's your stilt legged ones these are the ones from natural trap cave they all fall on the stilt legged span and then this is a smaller subset that are stout legged so based on meta Podio dimensions what you're seeing is actually just two species not three not four not five just two it turns out that's what the DNA is saying as well the DNA analyses suggest two species at natural trap caves so using some of the techniques we talked about earlier you actually can come up with similar results to what you're seeing based on DNA not to be outdone back in the American Southwest where I work there's also this site here called gypsum cave and this is again located out of Los outside of Las Vegas Nevada it is not open to the public and there are no fossils currently preserved in it but it was excavated back in the 1930s archaeologically and it did produce horse bones though sloths were the the big focus and of course it wasn't just sloths it's were people eating them that's always the focus in the Mojave Desert there are no fossils in the cave the fossils are preserved here at the Natural History Museum of Los Angeles County here's what some of the fossils look like and if you get in and look at the collections it's not permafrost and it's not a pocket of the Ice Age like at natural trap cave here it's dry heat these are truly mummified bones but you still have ligaments you still have tendons I didn't put these bones together for this picture they're being held together naturally they look that good and so with that kind of preservation you can get DNA out of these things too in terms of the size this is a metatarsal a hind foot bone and once again there's Stout small limbed animals here's your stilt legged animals and that bone plots right there it is a stilt legged horse based on its anatomy if you look at the DNA there it is right there Nevada 13,000 years old and it's plotting right in the middle of the Yukon and Wyoming specimens now I want you to notice that here's your key baleen horses here's your Asian Hemi onehans or stilt legged animals here's your Kyong and here is a separate lineage of stilt legged horses this was new when this study came out in 2005 prior to that every time scientists like myself talked about North American stilt legged horses we assumed that they were related to these guys kiyong and other animals like those from Asia that have long skinny legs we now know based on genetics that they're not closely related at all there are completely different lineage that presumably was doing something similar in addition at gypsum cave we had this hoof again that's the actual hoof of the horse with this phalanx on the inside and because the phalanx was in the inside we're able to take measurements off of it these are all of the small horses here the stout legged ones stilt legged ones all of them that hoof plots here so it's a large species of horse probably the same one that we've got from tule springs which is right next door and so once again it's another cave deposit where you've got two species of horse and so you seem to be seeing a similar thing at these cave deposits where the DNA is being found where you have only two species but that's not necessarily the whole story because it truly Springs where the bones are not well enough preserved to yield DNA we actually may have three species of horse that's our current interpretation beyond that though the DNA stuff is suggesting something else which I've already touched on that these Pleistocene horses are the same species as Przewalski's horses which in term are the same species as domestic horses and as a total aside I love this picture cuz I said smile and I got one I got two I got three how lucky was that anyway the reason I bring this up it's not just a moot point it's not unimportant because we have at least in the US we have problems with feral horse management these are feral descendants of domestic horses that are running in the western United States and I do not want to wade too deep into this because this is a very emotionally charged topic but the horses need to be managed and the current management generally has the animals being rounded up by helicopter and then stored and auctioned off and there are any number of pros and cons to that approach but it has received an awful lot of positive and negative publicity with people saying basically this is mistreating the horses why don't you just let them run free and the most recent argument has frequently been you should not just let them run free because their horses and they're wonderful and are pretty and spectacular but because they're natives because they are native to this continent that got their start here we know that they were here during the Ice Ages and so you're not dealing with a introduced feral animal you were dealing with a native who has returned to claim its rightful heritage in North America and this is actually granted this is from 2009 but still this is actually this was presented in Congress and there are still people who will make this argument and so it can be very significant what we say about Ice Age horses because it might have real time implications for what's going on with living wild excuse-me feral horses today if that wasn't enough there's this scold this is from gypsum cave we were very that's my colleague on this study Christina Lutz from Yale Peabody Museum and we were very happy because this skull was misplaced in the collections of the Natural History Museum it was actually not in the gypsum cave collection it was in the modern osteology collection because the preservation is so good somebody even wrote burro or a while to ass on the skull and they put it in the modern collection that's how good the preservation is and yet this is a thirteen thousand year old skull from gypsum cave and we've sampled it for DNA and this paper just came out end of last year here are your Kabbalah courses there's the modern domestic horse this is new world Kabbalah neck with some of the animals we've just been talking about that we're here during the Ice Age but are the same species as domestic horses here are everything else there's your kiyong there's your stilt legged horses there's your zebras they're the stilt legged horses from the new world plot completely separately and separated out many millions of years ago this is not based on mitochondrial DNA this is based on nuclear DNA and this is a relatively new study and that difference is so significant that it warranted the erection of a new species which we called Harrington hippos and it was just named at the end of last year and we named it after Charles Richard Harrington from the Canadian Museum of Nature who has been studying these animals for decades and is well known for his study of these animals so it seemed fitting to name this animal after him so that is a new genus of horse from North America which changes what we thought we knew about the extinction of these animals it changes what we thought we knew about the stilt legged relationship and so on it brings a whole new perspective on what's going on during the ice ages it certainly brings it to me because I've already told you about my background and how I think you can look at the anatomy of these horses and you can break it out and figure out how many species and how old they were and you think you're so clever and then along comes DNA and it says that you have these horses which I can look at these and if you've got the right bits I can tell them apart at a glance so can any competent professional they're that difference and yet genetically the suggestion is that they're the same they're potentially the same species which is not something you would expect on the other hand now you've got Harrington hippest which looks so much like a horse that somebody wrote wild-ass or burrow on the skull in pencil but we're leaving it there it looks that much and yet it has been separated from everything else from zebras from asses from horses for several million years and yet it looks identical so some things that are different but are the same some things that look the same but our total different and it leaves you wondering oh I forgot to change that those are supposed to be question marks I missed it the fonts wrong but anyway the leaves are wondering what's going on how do you resolve this and it's very frustrating for paleontologists because you don't want headlines like this waiting for you at the end of your career you actually want to think that what you're doing is contributing to to advancing science you don't want to figure that I've been measuring stuff for 30 years and suddenly it's all pointless and irrelevant and maybe dinosaurs were the way to go after all I don't know dinosaurs are actually easier nobody's gonna come along with dinosaur DNA I hope and tell you that Tyrannosaurus and Triceratops are the same thing I doubt very much that's going to happen but nevertheless I think paleontology still has something to add number one there are any number of fossils out there that don't yield DNA and so this is the only way you can get it information it may not be complete but it's all you've got and so second again using tule springs as an example we have what appear to be three separate species preserved at that site we can't test it with DNA because those fossils don't have any DNA in them and so you're stuck with the anatomy you're not going to be able to get around that in terms of using these horses these extinct horses to have implications for living horses particularly feral horses I would urge some caution the LaBrea horse is an example of an animal that I would say is distinct from Equus Scottie and potentially they are both distinct from Equus ferus the the species that is the same as the living domestic horse now that being said if tomorrow somebody gets DNA out of Equus cotta and proves that it's still the that it's the same thing as Equus ferus fine I will have to go along with that Equus occidentalis I think is still anatomically different and so far nobody's gotten DNA out of any of the fossils from the La Brea Tar Pits so until that happens you'd go with the anatomy it's all you've got which means that it's probably a little premature to start using them as proxies for living feral horses and this is where I hesitate to weigh in because again there's so much passion on either side of the feral horse question but over and above the taxonomy over and above the relationships of the ice age horses I would know that horses evolved as part of ecosystems you don't look at them in isolation at least you shouldn't and so in terms of feral horses they're actually animals that have been reintroduced to North America but the ecosystem where they evolved for 55 million years is no longer here they're no longer partitioning the environment with camels and bison and mammoths and mastodons and ground sloths it's just them the saber-tooth cats and the dire wolves that ate them are no longer around so it is a different environment so whether or not they are native is actually a red herring it shouldn't even be part of the equation it has no input I could go home to my home in Burbank California where I grew up I am absolutely a native I was born there I was raised there I spent way too long there according to my parents but I really suspect that the family living there now would have some serious objections when I said that's my room and why isn't my bed bait right I'm not just because I'm native doesn't mean I belong there now and I think that that's an analogy but the same thing is true for horses just because they may be native to North America doesn't mean that they can fit into today's ecosystems so personally I would not recommend using Pleistocene horses to inform decisions being made about living feral horses that being said I think we can use Pleistocene horses to make arguments and and in provide perspective on living horses altogether again the animals that we enjoy the domestic animals that we enjoy got their start with domestication because of their adaptations to ice age conditions and so when we study these animals we're actually learning more about how that partnership with horses came to develop and that leads to how did we build our civilizations so really again ice age horses are kind of the ink for that what I'd like to convey at the end here is that those studies are very still very much a work in progress that we are still right now there's a new genus named at the end of 2017 we just kicked wild horses out based on DNA last month there are very much still studies going on that are changing what we thought we knew about these animals and so it's actually a very exciting time and this is how science works it is not the end it's the beginning scientists aren't the ones who have all the answers they're the ones who ask the questions and then keep asking them and then keep finding answers and using more fossils and new techniques and so we're still learning about these animals and I hope you share some of the excitement fascination of them that I do because I think that they are one of the richest groups of organisms that one could ever have the opportunity to study and so with that thank you very much for your attention and if you have any questions I'd be happy to try to answer them you

Channel: Royal Tyrrell Museum of Palaeontology

Views: 39,362

Keywords: Speaker Series, Royal Tyrrell Museum, Palaeontology, Paleontology, Ice Age, Horses

Id: Tg3lt5zYO_k

Length: 53min 27sec (3207 seconds)

Published: Tue Mar 27 2018