The Story Of Texas Longhorns, As Told By Their DNA

After arriving on Spanish ships, North America's first cattle were left to roam the unfenced lands of Texas and Mexico, subject to hundreds of years of natural selection. Emily Jane McTavish, of the University of Texas at Austin, talks about reconstructing the history of longhorns through their DNA.

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IRA FLATOW, host: You're listening to SCIENCE FRIDAY from NPR. I'm Ira Flatow. Next up, longhorns, one of the most iconic breeds of cattle. You can find them in Texas today. But do you know where they came from? You know, in the audience, where they came from, yeah? No, see. Educational moment at this time. That's one of the things my next guest is piecing together by studying the tale told by the DNA of the Texas longhorn. Emily Jane McTavish is a Ph.D. candidate in the ecology, evolution and behavior program at the University of Texas at Austin. She's here with us at the Witte Museum in San Antonio. Welcome.

EMILY JANE MCTAVISH: Thank you so much. It's great to be here.

FLATOW: I just asked this Texas audience where their iconic cattle came from. They had no idea. Can you fill us in the history and the traveling of the Texas longhorn?

MCTAVISH: Yeah. I'd love to. Parts of the story are really straightforward, and then, what I think are maybe the more interesting parts are more complicated. But, as probably most people know, there were no cattle in North America at all prior to Columbus' voyage here. And the first cattle in North America were actually brought by Columbus himself to the Caribbean, to the island of Hispaniola, where...

FLATOW: On his second voyage?

MCTAVISH: Yeah. Exactly, in 1493, so a long time ago. And that must have been a really challenging voyage just thinking about the logistics.

FLATOW: How many miles on a boat with those cattle? I'm trying - wow.

MCTAVISH: I know it was - they actually made a really good trip on that voyage. It taken them, I think, close to 60 days the first time, and they made it in 21...

FLATOW: Wow. And how many? Have any idea? A dozen?

MCTAVISH: No. Most of the records have been lost. Based on what we know, the capacity of those ships were maybe 20 or 30, the - on that first voyage, and most of those would have been what are called bred heifers, so pregnant females who can kind of get more bang for your buck in terms of carrying those animals across.

FLATOW: And they came from originally from Spain.

MCTAVISH: So that's the interesting part of the story. The cattle were probably picked up in the Canary Islands, so an island that Columbus stopped off on that's just off of the west coast of Africa. And we know that Spanish and Portuguese settlers had brought cattle to the Canary Islands probably 15 or 20 years prior to Columbus' voyage. And that would be the most convenient place for him to have gotten cattle on that trip, and we know that cattle in the later few - in the next few decades were brought from there.

So they're probably brought from the Canary Islands and then into the Caribbean. And we do know that the cattle that were brought into the Canary Islands were from Spain and Portugal. So it's a kind of multistep process, but they were brought into the Caribbean in 1493 and by early in the 1500s were doing very well in Mexico.

FLATOW: They're in Mexico. And were they being raised as cattle? Are they roaming around or what?

MCTAVISH: Well, it's kind of a combination. In the first years after Columbus brought colonists to the Caribbean, the cattle weren't doing that well. The colonists weren't doing that well. They're supposed to be breeding them, but they were really hungry, and they were eating them a lot of the time.

FLATOW: They're eating, not breeding.

MCTAVISH: Yeah. It took them a while to get sort of stocks moving forward and breeding cattle. But by the 1520s, there was a very healthy population of cattle throughout the Caribbean Islands and into Mexico. And they actually adapted really well and did very well in Mexico with very little hands-on ranching.

FLATOW: So how did they wander north into Texas?

MCTAVISH: Yeah. I mean, basically, both on their own and tracking with people. That's one of the neat things about cattle is by looking into their DNA and tracking their migratory history, you're also tracking the history of the peoples that they're associated with.

FLATOW: So if we took - we have a couple of longhorn outside. If we took their DNA and I don't know if it's possible to compare it to, you know, Spanish - the Spanish DNA of their ancestors, would it look very much alike?

MCTAVISH: So that's where things get really interesting, I think. So we did know that these cattle were brought over by Columbus and Spaniards colonizing this area. But I've been doing research on the DNA of longhorns and comparing it to other breeds of cattle. Interestingly, using a lot of the same markers that the previous panel was talking about using, sort of looking forward for beef production, I'm using to look backwards of evolutionary history. We're using that same technology.

And so what we've found is that it does seem like this cattle do show that expected Spanish heritage or sort of Iberian Peninsula that Spanish and Portuguese heritage, but one thing that not a lot of people may know is that cattle weren't just domesticated once. The species that was allowed regenerative cattle was actually domesticated into completely separate places around the same time roughly eight to 10,000 years ago. So these separate domestication events have led to different lineages of cattle that have quite distinct DNA. And what we were seeing in Texas longhorns is a signature of this more Indian-like cattle, as opposed to European cattle, which is what you would expect from Spanish and Portuguese...

FLATOW: We were talking about the Indian Brahman.

MCTAVISH: Exactly. I - you know, I thought it tied in so well with what the earlier panel was saying about drought resistance.

FLATOW: So would this cattle be more drought-resistant than their ancestors?

MCTAVISH: Exactly. So this Indian breeder - Indian - they are called Bos indicus, or indicus breeds of cattle - are more tropically adapted and they tend to be more food-stress and drought-stress adapted. But the flipside of that is that they have not - they don't put on meat as rapidly and they're not efficient dairy cattle.

FLATOW: Can the horns adapt at all over the years?

MCTAVISH: Yeah. That's a really cool question because, obviously, looking at a longhorn - hopefully you guys in the audience here saw the ones that are outside. Their horns are crazy.

FLATOW: They're dangerous looking.

MCTAVISH: Yeah. And, you know, they seem almost like they wouldn't be that adaptive. It...

FLATOW: Yeah. What are they going to keep away with those horns? What are enemies are, you know...

MCTAVISH: Apparently, coyotes.

FLATOW: There are no dinosaurs around if they're going to attack, you know.

(SOUNDBITE OF LAUGHTER)

MCTAVISH: Yeah.

FLATOW: Coyotes.

MCTAVISH: Apparently. It seems like a lot of firepower for coyote use, but...

(SOUNDBITE OF LAUGHTER)

FLATOW: You know, I can see a coyote goes up to those - that cattle and says, I'm not taking that guy on, you know...

(SOUNDBITE OF LAUGHTER)

FLATOW: ...that sort of thing.

MCTAVISH: Exactly. And it's really surprising if you see them walking through a brush or trees or anything how aware they are of the shape and size of their horns. It looked like they just got stuck all the time, but they really - they can use them very delicately.

FLATOW: I'll bet they can. And so you're studying the DNA in these cattle.

MCTAVISH: Mm-hmm.

FLATOW: And then how do you study them? I mean, how can you tell the - can you tell the history of their domestication from the DNA?

MCTAVISH: So I would say partially. So what we have are a lot of DNA sequence markers scattered throughout the genome. That's what is cool about new technologies that are being developed. And what's great about working on cattle as opposed to, you know, any sort of, say, chipmunks, any kind of wild animal that you don't necessarily have the molecular tools that are being developed a lot result - related to the beef industry. So I'm able to use the same molecular tools to look at evolutionary questions. And so, yeah, we have markers that are on 29 of the - all of the cattle's chromosomes and that we can use to track history.

FLATOW: So have you become sort of enamored with the Texas longhorn?

MCTAVISH: I really have. My background is actually in working on reptiles and amphibians. I used to work on...

FLATOW: Wow.

MCTAVISH: frogs.

FLATOW: That's a jump.

MCTAVISH: Yeah.

FLATOW: That's a stretch.

(SOUNDBITE OF LAUGHTER)

MCTAVISH: Yeah. Exactly. But...

FLATOW: Quite a horn toad, my dear.

(SOUNDBITE OF LAUGHTER)

MCTAVISH: Exactly.

FLATOW: Sorry. I had (unintelligible).

(SOUNDBITE OF LAUGHTER)

MCTAVISH: It all ties together. But, yeah, I - most of my research is done on data that's actually sent to me. I don't get to do a lot of field work with the cattle. But my advisor, David Hillis, a professor at the University of Texas, ranches longhorns. And so I get to go out to his ranch and hang out them sometimes.

FLATOW: Mm-hmm. Now, you say that these longhorns are descendant from the Spanish cattle. And jus this week, I think, the running of the bull started in Pamplona, Spain. Would they be sort of longhorn-looking like these cattle here?

MCTAVISH: Yeah. That's a good question. They are similar looking and they share Spanish ancestry, but the fighting bulls of Spain are one of the earliest breeds of cattle that were specifically maintained as a breed, as opposed to what's called land races, which is just kind of the group of cattle that are in a place at a time.

So although longhorns would be related in ancestrally to these fighting bulls of Spain - actually, the fighting bulls were brought to Mexico about 50 years after longhorns and kept quite separately.

FLATOW: All right. Do you ever study how, you know, the great cattle drives of the longhorns at all? Has that interested you?

MCTAVISH: Yeah.

FLATOW: How do they begin? I mean, how do they always - you see them in the movies, the cowboys. The mythology that we think is right but is not, you know. If you all had this cattle roaming around, right...

MCTAVISH: Mm-hmm.

FLATOW: ...all by themselves...

MCTAVISH: Mm-hmm.

FLATOW: ...you just go out there and collect them?

MCTAVISH: I mean that's - that was the cool thing about ranching in Texas, is that you didn't need to own land because the people who did own land often couldn't afford to fence it. You just had to brand your cattle. And then if there are calves associated with cattle, you knew were yours. The next year you brand those. If you saw unbranded cattle, you grab them and brand them, too, and then that's how you knew they were yours.

(SOUNDBITE OF LAUGHTER)

MCTAVISH: And then - so actually, during the Civil War, a lot of people were otherwise were sort of busy outside of Texas, cattle really became - the population numbers became really high, and so at the end of the Civil War that there are a lot of these big cattle drives bringing cattle north.

FLATOW: So you - if you just found these longhorns without any brand on them, they're yours for taking.

Apparently. I think there's a lot of, sort of, social contract so, you know, you knew which were yours and you knew which were your neighbors. That's my understanding of it.

Wow. Wow. And do you study other cattle than longhorn also?

MCTAVISH: I do. I mean, I'm broadly interested. So when I'm talking about longhorns being brought by Columbus, that Spanish New World cattle, there are a lot of breeds that descended from that. So there are Corriente cattle of Mexico, a lot of different breeds of Northern and South American cattle and Central American cattle that show the same signature of Spanish ancestry.

FLATOW: Wow.

MCTAVISH: So I'm interested in all of those and in the patterns that led to what we see here today.

FLATOW: Well, we love your enthusiasm. I mean, it's to great to be - you actually - it looked like you love your job and what you're studying.

MCTAVISH: I do.

FLATOW: And that's good. And it's good that we have a - come to Texas and tell Texans about their own icon.

(SOUNDBITE OF LAUGHTER)

MCTAVISH: Yeah.

FLATOW: ...because they don't, you know, seems to know much about. Thank you very much Emily.

MCTAVISH: Thank you. Thanks for having me on the show.

FLATOW: Emily Jane McTavish is a Ph.D. candidate in ecology, evolution and behavior at the University of Texas at Austin, joining us here at the Witte Museum.

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