Not so long ago, there came an announcement from Yellowstone National Park concerning their Bison population. Unfortunately, this announcement did not serve as good news for the Bison, in fact, it was very bad. Because this announcement, called for their cull.
Perhaps unsurprisingly , this is not a new phenomenon. The bison cull is annual and since 1985, 8634 bison have been killed. This year, authorities hope to remove 1000 of the bison from the current population. In the summer, the herd consisted of approximately 4,900 animals, with the target population of the park remaining around 3000.
Although the cull has been going on for 30 years, the decision is controversial to say the least. The bison at Yellowstone are highly a highly important group, as their DNA contains 75% of the genetic diversity of the entire species. Put simply, they are the only ‘managed’ herds that do not contain any cattle genes, with their heritage spanning hundreds of years. Due to this, the bison in Yellowstone have been described as ‘pivotal to the long-term conservation of the species’.
So if this is the case, there must be some reason for this cull? Well, there is a reason, though, as ever, some would argue against it. In fact, the reasons for the bison cull may remind us of a very controversial cull in the UK. Basically, bison are culled as a means of controlling the spread of brucellosis transmission to domestic cattle. The fear of the spread of this bacteria also serves as a reason why bison are not allowed outside of the park borders. Granted, there is a small area where bison are committed to roam outside of the park, but this is for a very restricted period of time, and they are often hunted.
Unfortunately for the bison, their lifestyle has contributed to the arguments for the cull. In winter, bison migrate in order to find readily available food. The Montana livestock industry claims that such migration increases the risk of the spread of brucellosis. However, the argument of brucellosis has been described as a bit of a ‘Trojan horse’. Essentially, this reason has been exploited as a cover to support the cull. As ever and rather irritatingly for those for the cull, science is rather effective at undermining such an argument. Brucellosis can only be spread by infected pregnant bison cows in the last trimester of their pregnancy, which occurs in the months spanning February and April. During the cull, both bulls and calves are regularly killed, despite the fact that they cannot spread the bacteria. In addition, bison are not the only animals that can carry the infection. Elk can also be infected by the bacteria and are more likely to spread the disease to cattle. Indeed, there are no documented cases of bison ever transmitting brucellosis to cattle, with most infections being caused by elk.
Brucellosis is a bacterial infection, which causes cattle to miscarry their calf and it can be transmissible to humans and is known as undulant fever. However, the main pathway for the bacteria to be passed to humans, is through drinking unpasteurised milk. Nowadays, pasteurisation is common and the only way people become infected is from close contact with infected animals. However, as the science has begun to mount against the argument of brucellosis transmission, the latest case for the cull is ‘population control’ with herds growing ‘too large.’ Surely though, the reason for the herd being ‘too large’ is that their movements are restricted to Yellowstone to stop them from spreading brucellosis.
Sadly, the case of the Yellowstone bison mimics the case of our badgers in the UK. As in this country, culling is likely to continue despite mounting scientific evidence. There will always be cries of blue murder from the livestock industry, who wish to control the movements and populations of such animals. Although an unlikely pairing, the badger and the bison have one thing in common, they have fallen victim to blame. Blame, which is totally unjust and is not likely to disappear anytime soon.
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