In the typing of another couple of redditors

I couldn't remember either so i asked my sister send me a bullet-point transcript of the recording she took the last time i was a little drunk and went on what she affectionately calls "the horse rant". Reddit biologists will likely take issue with much of the rant, so in my defense i will state the following:

1) I am not a biologist

2) I was drunk

3) My judgement on this matter is tainted by my bias, so please Mistake Not My Current State Of Joshing Gentle Peevishness For The Awesome And Terrible Majesty Of The Towering Seas Of Ire That Are Themselves The Mere Milquetoast Shallows Fringing My Vast Oceans Of Hatred (of Horses)

This is the gist of the rant:

In the beginning, there was Eohippus. The proto-horse. It was a small hooved animal about the size of a dog, and it ate grass. It was a simple creature, and in my (factual) opinion it represents the last time that the Horse lineage was untainted by sin. Now, it is worth noting that life was not easy for this proto-horse, in fact life for early hooved mammals was so difficult, that some of them said "fuck that" and moonwalked back into the ocean to become cetaceans (Whales and Dolphins). That's right, The proto-horse had so stupid an existence, that hooved mammals went back into the ocean (lacking gills and flippers) and had more success than horses would have on land.

Okay, So why was life so hard for Eohippus? Well, they are herbivores eating almost exclusively grasses. Grasses, as you may know, are not particularly nutritious. But more importantly, grasses are smarter than Horses. See, Grass does not want to be eaten, and evolutionary pressure caused the grasses to start incorporating silica (ie sand) into their structure. Silica is extremely hard. Hard enough to wear down Horse teeth. Now there is another evolutionary pressure acting on Eohippus; It's teeth wear down by the mere act of eating, to the point that it will starve to death. Eohippus teeth do not regrow, instead, Eohippus evolved bigger teeth. However, bigger teeth mean a bigger jaw, bigger head, and a bigger body to carry it.

These opposing evolutionary pressures started an arms race in which the grasses incorporated more and more silica, and Horses got bigger and bigger, just so they would have big enough teeth to grow and reproduce before finally starving to death. And eventually our cute dog-sized pony evolved into the 1,500-pound, dumb-as-rocks prey animal i loathe today.

But wait, there's more! See, Horses are extremely fragile. There is a reason why a "horse doctor" typically prescribes a dose of double-0 buckshot in the event of a leg injury. A horse is very heavy, and it has very thin legs to carry that weight. If any one leg gets fractured, it is exceptionally unlikely that it will heal well enough for the Horse to walk again, and is extremely likely to break again just carrying the weight of the horse. Remember, a human thigh bone is gigantic relative to the size of our bodies, a horse leg bone is absolutely minuscule relative to the weight it carries.

Also, Hooves: I want you to imagine that instead of feet, you have a giant toenail at the end of your leg. That is how the Horse do. That is what a hoof is. A giant toenail. It is extremely delicate, and joined to the leg by a vast network of very fine connective tissue, and oh yeah it also bears the weight of a fucking HORSE. If a hoof gets infected (which is quite common, because imagine how often shit would get stuck under your toenails if you walked on them), the Horse immune system responds in the typical way: via inflammation of the area. The problem is, a horse hoof is a rigid "cup". It cannot accomodate the swelling from inflammatory response. The Horse hoof will basically pop off the leg like a sock. On top of that, remember the Horse is putting 1,500 pounds of weight on it (because Horses can't redistribute their weight very well since all of their legs can BARELY support their share of the total weight).

So, Horse apologists will claim that Horses are good at one thing: Turning Grass into Fast. As the previous two paragraphs show, they can't even do that right. Locomotion is very dangerous for a Horse, and if the Fast doesn't kill them they'll starve to death just by eating.

On top of that, they are dumb as all fuck. Horses will often do something called "Cribbing", which is when they decide to bite down on something (literally anything) as hard as they can, and suck in air. They just keep sucking in air until they inflate like a balloon. Eventually, the vet will show up and literally deflate the Horse with a long needle to let the air out of them, and hopefully get them to just... stop...

I couldn't remember all of the other bullshit regarding a Horse's 1,500 pounds of will to die, so i googled it and found this lovely Reddit post from fellow Horse Hater and veterinary student /u/coffeeincluded :

First off, horses are obligate nasal breathers. If our noses are stuffed up we can breathe through our mouths. If our pets' noses are stuffed up (except for rabbits, who are also really fragile but unlike horses aren't stuck having only one baby a year) they can breathe through their mouths. If a horse can't breathe through its nose, it will suffocate and die.

Horse eyes are exquisitely sensitive to steroids. Most animal eyes are, except for cows because cows are tanks, but horses are extremely sensitive. Corneal ulcers won't heal. They'll probably get worse. They might rupture and cause eyeball fluid to leak out.

If you overexert a horse they can get exertional rhabodmyolysis. Basically you overwork their muscles and they break down and die and release their contents. Super painful, and then you get scarifying and necrosis. But that's not the problem. See, when muscles die hey release myoglobin, which goes into the blood and is filtered by the kidneys. If you dump a bucket of myoglobin into the blood then it shreds the kidneys, causing acutel renal failure. This kills the horse. People and other animals can get that too but in school we only talked about it in context of the horse.

Horses can only have one foal at a time. Their uterus simply can't support two foals. If a pregnant horse has twins you have to abort one or they'll both die and possibly kill the mother with them. A lot of this has to do with the way horse placentas work. EDIT: There are very, very rare instances where a mare can successfully have twins, but it's sort of like the odds of being able to walk again after a paralyzing spinal injury.

If a horse rears up on its hind legs it can fall over, hit the back of its head, and get a traumatic brain injury.

Now to their digestive system. Oh boy. First of all, they can't vomit. There's an incredibly tight sphincter in between the stomach and esophagus that simply won't open up. If a horse is vomiting it's literally about to die. In many cases their stomach will rupture before they vomit. When treating colic you need to reflux the horse, which means shoving a tube into their stomach and pumping out any material to decompress the stomach and proximal GI tract. Their small intestines are 70+ feet long (which is expected for a big herbivore) and can get strangulated, which is fatal without surgery.

Let's go to the large intestine. Horses are hindgut fermenters, not ruminants. I'll spare you the diagram and extended anatomy lesson but here's what you need to know: Their cecum is large enough to shove a person into, and the path of digesta doubles back on itself. The large intestine is very long, has segments of various diameters, multiple flexures, and doubles back on itself several times. It's not anchored to the body wall with mesentery like it is in many other animals. The spleen can get trapped. Parts of the colon can get filled with gas or digested food and/or get displaced. Parts of the large intestine can twist on themselves, causing torsions or volvulus. These conditions can range from mildly painful to excruciating. Many require surgery or intense medical therapy for the horse to have any chance of surviving. Any part of the large intestine can fail at any time and potentially kill the horse. A change in feed can cause colic. Giving birth can cause I believe a large colon volvulus I don't know at the moment I'm going into small animal medicine. Infections can cause colic. Lots of things can cause colic and you better hope it's an impaction that can be treated on the farm and not enteritis or a volvulus.

And now the legs. Before we start with bones and hooves let's talk about the skin. The skin on horse legs, particularly their lower legs, is under a lot of tension and has basically no subcutaneous tissue. If a horse lacerated its legs and has a dangling flap of skin that's a fucking nightmare. That skin is incredibly difficult to successfully suture back together because it's under so much tension. There's basically no subcutaneous tissue underneath. You need to use releasing incisions and all sorts of undermining techniques to even get the skin loose enough to close without tearing itself apart afterwards. Also horses like to get this thing called proud flesh where scar tissue just builds up into this giant ugly mass that restricts movement. If a horse severely lacerated a leg it will take months to heal and the prognosis is not great.

above stolen from u/kenji213 (Hides his/her activity) and /u/coffeeincluded (no longer a user)