After 120 years, Yellowstone bison are a single breeding population
53 comments
·March 5, 2025y33t
sidewndr46
It was a deliberate attempt to deprive Native Americans of their historical means of support. You can't besiege a Native American city because they had already been pushed off their historical lands. But if you can eliminate a major source of food for them, it's possibly even more effective.
In general people under-estimate the capability of humanity to eradicate other forms of life. We've managed to eliminates organisms as plentiful as things like rinderpest for example. Large animals are actually easier. Were it not for a last minute change, almost all forms of whales would have been extinct in the 20th century. We've been the most advanced life form on Earth for a long time, possibly even before modern humans arrived. But in the past 1000 years or so we really became the most dominant life form. Our population has exploded and we can pretty much push out any other form of life we choose.
snowwrestler
Latest estimates I recall are that humans and our livestock together comprise over 90% of the total mass of land animals globally. All wild animals together are less than 10%.
The mental picture of a wild Earth on which humans live is now outdated. The Earth has become a human place, with essentially some open-air zoos containing the few wild animals we have chosen to not kill.
lalalandland
Insects comprise a total weight to about 1 billion tons.(1) Which is roughly the same as the weight of all people and farm animals on Earth combined. (1) https://www.jpost.com/environment-and-climate-change/article...
null
buerkle
https://en.wikipedia.org/wiki/Rocky_Mountain_locust is an interesting example of eradicating an organism. From massive swarms of locusts to none in under 30 years.
fanatic2pope
Along the same lines is the passenger pigeon.
Miraste
This is true of macro life forms, but rinderpest is a bad example. It's one of only two diseases we have ever been able to eliminate. Both of them were viruses-we've never stopped a bacterial disease, and with the increasing failure of antibiotics, that's only going to get worse.
cyberax
> It was a deliberate attempt to deprive Native Americans of their historical means of support.
No, it was not. The bison population collapse was not something expected or planned. One year the bison simply disappeared (1882).
The bison ecosystem in North America was deeply unnatural. Bison are fast-replicating herbivores that don't have any natural predators! This only happened because Natives exterminated almost all the large predators.
Such systems almost always go through boom-bust cycles, and that's exactly what happened. The migration patterns were disturbed by railroads, and that likely led to the spread of the Texas tick fever and anthrax among the bison population. They have around 90% death rate, and that's what caused the population collapse.
However, this time the population did not recover by itself.
> But if you can eliminate a major source of food for them, it's possibly even more effective.
It's the same nonsense as giving smallpox-impregnated blankets used to exterminate populations.
onychomys
Do you have any evidence for the claim that it was disease rather than the immense slaughter?
SpicyUme
Grizzly bears hunted bison and were present in the plains states down through Texas and into Mexico. The last Grizzly in Arizona was killed later than the last one in California.
jurenbert
[dead]
openasocket
There are several examples of this in other species. The Przewalski horse is probably one of the most dramatic examples. The population was reduced to around a dozen individuals, all in captivity. After an intensive breeding and reintroduction program, the population is now around 2,000, with several hundred of those in the wild. There's also the Père David's deer. It's an interesting species: the only semi-aquatic deer species. It has webbing between its hooves and eats aquativ plants (along with grass). They were hunted essentially to extinction in their native territory in China, the only remaining individuals were a handful taken by missionaries (including Père David, their namesake). Today their population is over 8,000, with hundreds reintroduced to the wild.
It's sad to think about, but it's also hopeful in a way. Humanity as a whole nearly killed these species, but a few dedicated individuals were able to save them.
PlunderBunny
The Black Robin in New Zealand is almost the most extreme example of a recovery from near extinction: Just 1 female and 5 males in the early 1980s have now bred a population of around 300 individuals. There's an interesting story in the wikipedia page [0] of 'edge laying' egg behaviour, and how humans initially corrected the problem but later had to stop to ensure the behaviour wasn't propagated.
karmakurtisaani
Something similar also happened in Europe. They were eradicated everywhere but a small natural park in Poland. Now they are being reintroduced, although I don't know where they will find the space.
sidewndr46
Somewhat curiously, there is another recently extinct animal the "Auroch" which was hunted to extinction as well. As recently as 1000 years ago they were quite plentiful, but completely extinct by the time Europeans started moving to the Americas
WorkerBee28474
There have been some, let's say, 'interesting' attempts to recreate the species via back-breeding [0]. They seem to be having some success.
[0] https://www.independent.co.uk/news/science/nazi-super-cows-e...
dendrite9
Lions were also roaming Europe relatively recently, likely into the middle ages.
bkovacev
Fruska gora, a mountain region in Serbia, has acquired or were gifted 5 European bisons from Poland[0]. It's always heartwarming to see a country working extremely hard to preserve any species. It was devastating news for a lot of people that one of the bisons, Djuka, passed away recently (not to be confused with a Serbian politician Vladimir Djukanovic also known as bison Djuka[1]).
[0] https://www.gov.pl/web/srbija/poljski-bizoni-u-nacionalnom-p...
gooseus
https://www.pbs.org/kenburns/the-american-buffalo
Wonderful documentary.
TomBombadildoze
Buffalo also feature prominently in The West, another fantastic Ken Burns documentary.
david38
This is not true. An officer from the US was sent to protect the Yellowstone herd at some point. IIRC he had previously been assigned to fight Indians and had a track record for “effectiveness” aka modern day war crimes. Apparently this was more a personality trait than particular hatred of the tribes of the plains because when he was ordered to protect the bison, he did it with the same energy and “effectiveness”.
Not claiming he was the only one, but possibly the only one with enough guns, soldiers T his command, the backing of an executive order, and a dim enough view of human life to move the needle as much as he did.
I need to go research this again and erase this comment if I’m talking trash or update it if I’m not.
writtenAnswer
Makes sense. In Zoo tycoon, these fuckers kept breeding like no one's business.
kaikai
I have mixed feelings about this news, because while it’s good to have more genetic diversity, it makes it easier to justify culling animals. Having multiple herds with distinct breeding populations means each herd is more likely to get protected.
The us government culls bison from the Yellowstone herd every year, to discourage them from leaving them park and competing with cattle grazing on public lands.
Bison are managed completely differently than other wildlife in the area like moose and elk, because they compete with cattle. They’re forced to stay inside the higher elevation park boundaries, even when the snow is too high for them to forage effectively. They get hazed by helicopters, chased by DOL agents and rangers on horseback, and forced to run miles through snow to cross that invisible line back in Yellowstone. I’ve seen newborn bison calves with broken legs from getting hazed back into the park.
If they were allowed to migrate seasonally and breed normally, they would have a much larger range and population.
Source: I used to live on the park boundary and was part of a group documenting bison management.
_DeadFred_
Does the land they keep the bison from going to happen to be federal land the cattle farmers lease? Since you say DOL agents it sounds like. So lame. Prioritizing private ranchers on the peoples' land.
kaikai
It’s a mix of federal, state, and private land. There was a group of private landowners that fought for years to keep the DOL from hazing bison off of their PRIVATELY owned land on Horsehead Butte.
And yes, that’s the Department of Livestock. There’s an interagency management group that handles bison in the area, including the Department of Livestock and at times Homeland Security. They also run catch pens near Gardiner, where they round up wild bison and send them to slaughter houses.
onychomys
There's actually LESS genetic diversity in a single breeding population than in two separate ones. When you have two, they can drift in different directions or be subject to different selection pressures. With just one, all of that stuff is swamped out.
FuriouslyAdrift
There's also a herd at Custer National Park comprised of 2 breeds ("Minneconjou" and "Humbolt")
kapitanjakc
Isn't interbreeding bad for their health?
Genuine question.
Is it interbreeding in a way like all bisons present now are sharing the ancestors or is it like it's all a single family of 6k bisons now ?
InitialLastName
The notable discovery is that, where the evidence a few decades ago was that the bison were breeding in their historical herds (so multiple, smaller genetic pools), they now appear to be breeding between herds (so a single larger, more diverse genetic pool).
AIUI with small populations, more variation in breeding between groups is a good thing, because it spreads genetic diversity across the whole population.
Sharlin
You probably mean inbreeding. Interbreeding is good. It is good that the bison herds mingle and interbreed.
Anyway, for mammals an initial population of a couple dozen individuals (assuming they're reasonably genetically diverse in the first place) is plenty enough to produce a population of any size without problems.
onychomys
There's a general guideline called the 50-500 rule. You need at least 50 animals to avoid immediate inbreeding (and also stochastic extinction from a fire or flood or disease etc), and about 500 to have a genetically healthy population. That varies some after a bottleneck event since your genetic population will be functionally less than your actual physical one, but it's a decent way to approach the problem.
ch4s3
Having a single breeding population across the park creates more genetic diversity than would be present in isolated herds.
diggan
Compared to the alternative of the species not surviving at all, it seems like the better option :)
Besides, it seems like they think it's genetically healthy, so doesn't seem like a problem. I'm assuming they've verified this somehow.
> Today, the Texas A&M researchers report that the Yellowstone bison population appears to be functioning as a single and genetically healthy population that fluctuates between 4,000 and 6,000 individuals.
nonethewiser
> Compared to the alternative of the species not surviving at all
How about compared to two distinct herds?
casenmgreen
Getting that "living on top of a volcano" risk feeling :-)
gavindean90
At least two groups are now breeding as a single population. The genetic diversity might be more spread out over the population. As I understand the article there were two functionally separate groups as late as 20 years ago (already 100 years after the introduction of the Texas bison to the original Montana heard) and now they are recorded as being a single population.
pinkmuffinere
Biology is not my area of expertise, but: Interbreeding is bad when it’s a small population interbreeding for a long long time. From the article it sounds like they aren’t worried about the genetic diversity of this 6k bison herd. I’m sure it would be better to have more diversity, but that’s hard to achieve with animals brought back from near-extinction.
darth_avocado
There are a lot of private herds. But a lot of them have been bred with domesticated cattle and do not have the pure bison DNA in them. They can be used as a last resort. The solution here would be to slowly start separating herds to more locations away from Yellowstone. Over generations, the genetic makeup will separate enough to be considered separate populations.
thrance
> Bison like those in Yellowstone once suffered a population crisis that conservationists call the "population bottleneck" of the 19th century. By the early 1900s, American bison numbers had been reduced by 99.9% across North America and only 23 wild bison were known to have survived poaching in Yellowstone.
So at their worst this particular population only had 23 individuals left. Interbreeding is bad insofar as it increases the chances of passing harmful recessive genes to younger generations.
I saw a documentary (PBS? Ken Burns? Something like that) about bison and I'm astonished we have any left today. They had a couple of private herds and a handful of individuals in zoos, and that was just about it. That's after having a population, less than a century previous, that produced regular accounts of covering the land for as far as the eye could see. The only reason we didn't wipe them out completely was because of just a few people working independently of one another who thought it would be a shame to see them disappear.