There are animals everywhere. They’re in zoos, public and private. And they all eat. And as a result, they’ve all got teeth more busted than a hillbilly’s after a meth binge.

Animal dentistry is a complex job, and there are five animals in particular they don’t look forward to…but at least the animals in question are cuddly.

5) Rattlesnakes

Snakes of all sorts rely on their teeth. Their teeth are their defensive mechanism, and they tend not to have a lot of them.

So, understandably, they’re a little shy about having their mouths pried open and letting the dentist take a look around, and none moreso than the rattlesnake. Which, let’s not forget, has a nice big mouth full of hemotoxic venom. So, yeah, good luck with that toothbrush.

4) Horses

Horses, poor guys, suffer from a whole host of dental problems. A horse’s teeth will grow and keep growing until it’s about 30, and the only method it has of grinding those teeth down is the silica in natural grass.

You’d think grass wouldn’t make your teeth sharp, but you’d be wrong. You’d be really, really wrong.

Horses can have teeth literally as sharp as razors. And if it hasn’t been getting natural grasp, it’s got a bunch of jagged teeth in there, all razor sharp. Plus, the only way to treat a horse tooth problem is to get in there, usually with a rasp or some other terrifyingly oversized implement, and get those problem areas sanded down.

So, let’s review: you’re sticking your hand down the throat of a powerful animal with jaw muscles designed to press down and grind, holding a rasp, which you’re going to run across its teeth.

Unsurprisingly, doing this on a regular basis can end badly for the horse dentist doing it, and this job is why they invented horse tranquilizers.

3) Koala

What, you say? The cuddly koala? How could that be dangerous?

Well, lots of ways. But really, we’re talking about the koala’s mouth, which is designed to do one thing: eat eucalyptus leaves.

A koala eats about a pound of eucalyptus leaves a day. Eucalyptus leaves happen to be insanely poisonous to everybody but the koala, and also happen to be extremely tough. As in, it takes real force to tear them.

Then consider the koala grinds these bad boys into a fine paste. Now consider your finger, in there, when the koala bites down.

They’ve been known to break fingers or otherwise injure would-be dentists, and can even bend steel instruments. Fortunately, the eucalyptus diet means that unless a koala has a serious problem, a dentist usually isn’t necessary.

2) Polar bears

Contrary to popular belief, a well-fed polar bear is actually not that hostile. True, a hungry polar bear will end you faster than the Mafia. But they’re in a zoo, they’re well-fed, so they tend to be less likely to rip you to teeny little pieces, and then eat them. Notice we didn’t say they won’t do this, just that they’re less likely to do it.

Still, we’re talking about the largest terrestrial predator here: you literally have to start poking squid in the ocean to find something bigger and more likely to eat you. And it also like to be alone. Let’s see here: a solitary meat-eating animal that weighs a ton and a half. Boy, that doesn’t sound dangerous to treat. Not at all.

1) Hippos

Hippos are cuddly-wuddly little creatures, according to Disney. In reality, they’re terrifying murder machines. Seriously, do not cross the hippo.

Why? Well, for starters, it’s insanely territorial. A hippo, which let’s not forget weighs several tons, will immediate attack anybody invading its personal bubble, and that bubble can be pretty big. And unlike most people using the term “personal space”, a hippo will actually be aggressive.

Secondly, it’s got big teeth, and lots of them, which it will use to make life miserable by trying to gore you with them. So, essentially, you’ve got a lot of work to do on an animal who doesn’t like you being within thirty yards of it and will kill you with what you’re scrubbing. Have fun with that.