On the one hand, this doesn't mean that it would be beneficial for a herbivore to eat meat all the time - clearly, they evolved a mostly herbivorous diet that meat provides a protean supplement to.
On the other hand, it does show that a voluntarily purely vegetarian diet is an artificial human creation. Yet, humans impose all sorts of artificial strictures on themselves and live to tell the tale.
> On the other hand, it does show that a voluntarily purely vegetarian diet is an artificial human creation.
That's an odd comparison. For the hare, if the choice is "starve in the middle of winter" or "eat meat", it's not surprising they eat meat. I think to say that a "voluntarily purely vegetarian diet is a purely human creation" is true not because of the vegetarian part, but because of the "voluntary" part. Most humans have the luxury of being able to choose a large part of their diets, while many wild animals are usually in a constant state of semi-starvation.
It's unfortunate you're being downvoted, because you are broadly correct. The US was the first country to achieve a sustained, structural food surplus nationally. By 1920 it was saving millions of Russians from starvation via its immense food surplus. Millions of Europeans fled their homes over decades to come to the US because of food scarcity and starvation back home. During most of the 19th century starvation was still a common problem across nearly all of continental Europe. All the way back to the late 18th century, the British soldiers and Hessian mercenaries that were raping and pillaging their way across the colonies couldn't believe the general prosperity that New Englanders were enjoying (such that they had any cause to be rebelling; see the book 1776 by McCullough). Until the last 40 years, the US had typically been far wealthier and with a far greater national food surplus than most of Europe. Even now, the US GDP per capita is typically 50-60% higher than the EU GDP per capita. The Irish, Germans and Italians that fled Europe to the US did so because of extraordinary poverty and famine. The standard of poor in the US today is greater than 10x higher than the floor on poverty in Europe, which you see in countries like Moldova, Ukraine, Bulgaria, etc.
"Irish, German, and Scandinavian immigrants arriving during the 1840s and 1850s made up the second wave of European immigration, fleeing famine, religious persecution, and political conflicts."
Interesting to me that most of the countries high up on the list are dominated by indigenous populations that are even less able to deal with modern carb-rich Western diets than European-based populations. E.g. I'm assuming New Zealand is so high because of Maori people.
Maori make up just 15% of the NZ population. They do however have more obese despite fewer who are only moderately overweight. Since the BMI ranking is by arithmetic mean, extremely fat people will have an outsize effect.
There's speculation (not sure if it's more substantiated than) that the obesity rates seen in the Pacific islands may also involve selection for humans who could amass energy stores necessary for long oceanic voyages.
But my point is in the wilderness the threat of starvation is an ever-present risk, so it helps not to be choosy. Modern humans in first world countries don't have that problem.
There are significant anatomical differences between herbivores and carnivores. Their digestive systems are specialized to processing either animal or plant based protein and fiber more efficiently. Herbivore teeth differe greatly from carnivore teeth and are specialized for grinding where as carnivore teeth tend to be specialized towards biting and tearing.
Humans are omnivores. Like Black bears, raccoons etc. Our digestive system is capable of processing either plant or animal based protein fairly efficiently. Though there are some plant based proteins humans struggle to digest.
There's a difference between eating your dead in a survival situation and consuming animal protein over an extended period of time. It's not that they're not capable of it. It's that their bofies aren't adapted to it and it's inefficient for them to process over long periods. Their bodies are adapted to process plants more efficiently so they do. If they're starving they'll eat what they can. Biologists have known this for a long time. This isn't new information. The differences in teeth and intestinal structure are very distinct. We've cutting open animals for a long time.
Obligate Herbivores will have extra stomachs and digestive chambers, special reguritating mechanisms to allow rechewing of food.
Obligate Carnivores tend to have shorter simpler digestive systems not capable of processing plant material.
If anything I would be more impressed to find out some carnivores were found relying on plants than the other way around. Plants are harder to digest than meat is. A herbivore occasionally eating meat really isn't that rare or anything to get excited about.
Discovering a tiger that lived on bamboo or something now that would be something new and would maybe be something we could use to start rewriting what we know about digestion.
It's not just hares; deer and horses (for example) also eat meat if they can get it. They usually go for injured birds or squirrels that can't run away from them (naturally a horse isn't a good bird predator).
On the other hand, it does show that a voluntarily purely vegetarian diet is an artificial human creation. Yet, humans impose all sorts of artificial strictures on themselves and live to tell the tale.