@jasonhernandez74
But our long-ago ancestors, presumably, chose to mate with Neanderthals and Denisovans. Bison being deliberately hybridized with cattle is more like if some twisted person forced a human to mate with a chimp. It was an act of violence against their species. The cattle genes in today’s bison are essentially our territorial marker on them, showing our presumed ownership of the species.
IIRC bison and cattle will naturally hybridize in the wild if allowed to cohabitate, much in the same way as the various Canis species (e.g., coyote/gray wolf/red wolf/jackals) will with each other. Indeed, most of the Bos/Bison species are known to interbreed with each other at the edges of their various ranges. Wisent (Bison bonasus) have even been suggested to have arisen through hybridogenesis, but this is still controversial. Many mammalian species complexes will do this, which can make reconstructing taxonomy and phylogeny a bit tricky.
Most of the cattle genes in bison likely arose from wild bison freely hybridizing with escaped or semiferal Bos taurus, at first probably feral individuals from the cattle the Spanish brought over (some of the Iberian-descended breeds like the Texas longhorn had a phase of about three centuries of living an outright feral existence with almost no human interference from ~1500 to ~1700-1800 before being recaptured). Then, as Anglo settlers moved further west, you still had cattle escaping from captivity and becoming feral (this was a known issue in places like Wyoming). Bison-cattle crossbreeds are known as far back as 1749, whereas intentional cross-breeding in captivity didn’t happen for another century.
Additionally, I would bet that a lot of this hybridization comes from the period where bison herds were decimated and nearly driven to extinction (i.e., late 19th century), given in those scenarios bison had few options for mates and thus might be more likely to mate with unusual partners, similar to what wildlife biologists have documented for Canis spp. and what has been suggested for the Neanderthals. This is mostly based on the fact that most of these herds are descended from a few individuals captured during that time. The linked genetic analysis also suggests the cattle ancestry mostly stems from the founder effect: a couple of bison had some cattle ancestry and because the extant population had a very small number of founders (~50 for all of the herds outside Yellowstone, and then another ~50 for Yellowstone), and thus backcrossing spread their genes throughout the population.
Notably, even though humans have bred “beefalo” in captivity, most of these enterprises were rather gimmicky and the animals remained in captivity. Allen even mentions in some of these cases that bison and domestic cattle would eagerly breed on their own in captivity. Indeed, most ranchers actually want bison nowhere near their animals, because they fear they could act as vectors for brucellosis (the evidence is…debatable) or because they could disrupt the careful management and breeding of their animals. It’s not impossible, but highly unlikely that the cattle genes in wild bison (or, in the context of this discussion, the herds in the various parks and preserves) are intentional.
Thus, this statement is unintentionally inaccurate at best, or deliberately framing things in a sensationalist manner to try and push a particular conclusion at worst (i.e., describing hybridization as “an act of violence against the species”, when humans may not even have been involved). If anything, our own species’ obsession with maintaining genetic purity of a lineage when many species freely hybridize when they get the chance, seemingly ignoring the idea of a consistent species concept, could be described as equally hubristic.
@cmcheatle
That being said, it will likely never disappear entirely. The human experience you cited covers thousands of times more generations, yet a measurable amount persists.
Unless there is a reproductive disadvantage to it being in the genome, it likely will be there in some amount for as long as bison persist.
Interestingly, it’s kind of mixed. Bison with cattle ancestry anecdotally exhibit lower levels of aggression than wild pure bison. “Beefalo” definitely do, but it’s not 100% clear if bison that have 1% cattle ancestry do (e.g., like the Custer State Park Herd). The suggestion has been that bison with cattle ancestry are less likely to win in dominance disputes and thus less likely to breed, but at the same time might thrive because they are easier to transport or less likely to get in trouble. Plus, in the initial capture of the last remaining wild bison in the 19th century for captive breeding, animals with hybrid ancestry would have been more likely to survive. This may be why the genes aren’t completely selected out.
I’ve heard similar concerns from zoo scientists that captive populations of many animals (e.g., big cats, wolves, bears, ungulates, etc.) are likely artificially selected for increased “tameness”, because non-tame individuals don’t adapt well to captivity. This has raised concerns whether individuals involved in captive breeding programs can be used to repopulate the species at all, because they’ve gone through a selective bottleneck and have potentially lost some of their aggression.
@pmeisenheimer
The first rule of iNat is “assume that people mean no harm”. Regardless, recategorization is not deletion.
Check the comments of the person this was said in response to. The user explicitly said doing so would be ‘useful for making a point about today’s concept of “conservation".’