Caution: These Types of Pets Should Never Live Together

Lots of us are animal lovers. Maybe you even wish you had Snow White’s fairy tale life, where several little animals help you brush your hair and clean your house. Unfortunately, real life isn’t as magical, and animals don’t always get along.

Here are some species of common pets who are difficult, if not downright dangerous, to keep in the same house.

1. Birds and most cats

kitten is playing with colorful paper cranes

Cats instinctively want to go after birds. | iStock.com

Cats are excellent hunters (that’s why most feral cats you see look pretty well fed). And they typically won’t differentiate between a wild and pet bird. According to The Spurce, “If you have a cat and want a bird or vice versa, you should understand that in nature, the two would be enemies — predator and prey.” Cats can cause serious injury to a bird, and larger birds can do some damage with their beaks. So unless you always plan to keep these pets under close supervision, don’t house them together.

Next: You don’t want to play the cat-and-mouse game.

2. Rodents and most cats

cat watching mouse

Cats love to hunt rodents. | iStock.com/Fergregory

Tom and Jerry were entertaining, but your cat chasing a mouse around the house probably wouldn’t be so fun. Just like cats could easily harm a bird, they could be deadly to a pet rodent, too. According to Petful, it’s “a sense of smell, a sense of hearing, a sense of taste, very sensitive whiskers, and an instinct for ‘the chase’ that makes your fluffy kitty cat a well-oiled mouse-hunting machine.” There’s no way to completely trust a pet cat around a rodent because you never know when that instinct will kick in, so these aren’t pets you want under the same roof.

Next: Even the same type of animal doesn’t always flock.

3. Large birds and small birds

four blue and gold macaws on tropical beach

Birds of the same type usually do fine, but pairing them with others doesn’t always go well. | iStock.com/Ake1150sb

Smaller birds tend to be fine when housed together. They are flock animals, after all. However, according to Beauty of Birds, “Small birds are intimidated (and stressed) by larger birds (even peaceful ones) when both are confined together in the same space.” Signs of stress might include feather picking (self-mutilation), fighting, and chasing. Plus, those big beaks could seriously injure or kill a smaller bird. So play it safe, and stick to birds of the same feather.

Next: Here’s another pet who doesn’t play nice with its own species.

4. Hamsters and more hamsters

golden hamster

Hamsters are loners. | iStock.com/Mu_mu_

If you thought a hamster would much rather play with a friend than run on a wheel all night, you’d be wrong. These little fuzzballs are highly territorial, according to the Humane Society of the United States, and they’re best kept individually. They’ll actually use those pointy teeth to seriously injure another hamster on their turf. Plus, hamsters are on the low end of the food chain when it comes to larger pets, so be sure to keep their cages far away from any hunters, like cats or dogs, in your home.

Next: They’re called hunting dogs after all.

4. Most dogs and small animals

Dog meets a rabbit

Dogs have that hunting instinct. | iStock.com/ZlatkoNečevski

Some dogs have that instinct to go after small animals and birds, whether they’re inside or outside. And most dogs like chasing moving objects, regardless of whether they want a meal. “While predatory behavior toward small animals may only go as far as the chase, with no harm done to the animal, some dogs may proceed further, depending on the situation and their excitement levels,” Vetstreet reports. So, if you have a dog and a smaller pet, heavily supervise whenever they’re together and keep them separate otherwise.

Next: These two species look a little alike, but they shouldn’t ever meet.

5. Rabbits and guinea pigs

guinea pig

Guinea pigs and rabbits pose dangers to each other. | iStock.com/DevMarya

Although rabbits and guinea pigs seem like they should get along because of their similar size and fluffiness, that’s not always the case. According to the Royal Society for the Prevention of Cruelty to Animals, the species behave and communicate differently, and rabbits are capable of bullying or harming guinea pigs. Plus, rabbits carry bacteria that could cause a serious respiratory disease in guinea pigs, so it’s best to enjoy these fluff balls separately.

Next: This pair has a rivalry as old as time.

6. Some cats and dogs

Kitten hisses at puppy

These two have their differences. | iStock.com/Voren1

We know, we know. Lots of people have cats and dogs. And typically it’s a tolerant, if not genuinely loving, relationship. However, some members of each species never get along and could actually end up hurting the other. Hunting dog breeds obviously might want to hunt cats. And even herding dogs might drive a cat nuts trying to herd it around the house. Plus, a friendly but energetic dog trying to get a cat to play might get a nasty swipe from some kitty claws.

Next: Ferrets are more vicious than you might think.

7. Ferrets with other small mammals

ferret

Ferrets aren’t always friendly to other pets. | iStock.com/GlobalP

Unlike a plant-munching rabbit, ferrets are actually carnivores. And though they make fun little pets, they’re smart and like to get into trouble. The Spruce reports that ferrets and other small pets don’t mix well because “quick movements by these small animals may trigger a predator-prey instinct in your ferret.” Therefore, it’s best to keep these animals separate. On a positive note, it is possible to teach dogs, cats, and ferrets to co-exist.

Next: Birds could also be their target.

8. Ferrets and birds

six parakeets

A ferret could do some damage to small birds. | iStock.com

Just like they’ll hunt small mammals, ferrets will attack a pet bird — even a large parrot. “Ferrets are sly and will find a way to wiggle into your parrot’s cage looking for a tasty meal,” The Nest reports. Therefore, to avoid a large vet bill, it’s best to never to keep these pets together.

Next: These guys are sharp.

9. Hedgehogs and other pets

hand holding hedgehog

There are several dangers surrounding hedgehogs. | iStock.com

Hedgehogs have seen a rise in popularity as exotic pets, Vetstreet reports. But they shouldn’t come in contact with any of your other pets. For one thing — and this really should be a no-brainer — they’re sharp. They don’t release their quills like porcupines, but those pointy things can still do some damage, even to a much larger animal. But on the flip side, a curious cat or dog could seriously injure a hedgehog, too. Plus, as if the quills weren’t enough, hedgehogs carry bacteria that can sicken other species.

Next: Slow and steady, these guys should live alone.

10. Reptiles and other pets (including other reptiles)

box turtle in water

Turtles carry salmonella. | Justin Sullivan/Getty Images

Reptiles make cool little pets, but there are several reasons to keep them separate from other animals. For one, reptiles carry salmonella, according to the Centers for Disease Control and Prevention, which can infect other animals, including humans. Additionally, larger animals, such as cats and dogs, can easily harm a smaller reptile. And reptiles, especially snakes, might attempt to prey upon your pet birds or rodents.

Even different types of reptiles aren’t suited to co-exist, according to Vetstreet. They have varying temperature, diet, and light requirements, as well as conflicting behaviors. Also, some might naturally carry diseases that would infect another type of reptile.

Next: It’s not easy being green.

11. Amphibians and reptiles

Giant African bullfrog

Amphibians pose some health hazards. | iStock.com/Bgton

Unlike most reptiles, there are some types of amphibians who can live with other amphibians. But they, too, shouldn’t live with reptiles. Vetstreet reports amphibians and reptiles have different diets and environments, and the germs each carries could be detrimental to the other. So keep Kermit away from your Ninja Turtles.

Next: Fish are friends — and sometimes food.

12. Fish and some other fish

fish in aquarium

Certain fish might view other fish as a meal. | iStock.com/Gracethang

Community aquariums can be a lot of fun to set up for aquatic lovers. But not all fish are as friendly as Nemo and Dory. Pet Helpful has a rundown of fish who are compatible in a community setting and some who aren’t. In order to have a successful tank, do your research on the various types of fish, and make sure everybody has plenty of space to just keep swimming.

Next: You don’t need to carry on the species.

13. Unfixed male and female anything

Two Chihuahuas riding in stroller

You don’t need any more fur babies. | iStock.com/Thisislover

Listen to Bob Barker, and spay and neuter your pets. There are too many homeless dogs and cats dying in animal shelters every year for you to allow your pets to procreate. Plus, if you have any exotic pets you allow to reproduce, their babies require very specific care. Those infants might fail to thrive, resulting in some heartbreaking losses that could have easily been prevented.

Additionally, in many species, animals who aren’t spayed and neutered tend to have more behavioral problems, such as marking and aggression. According to WebMD, they also have higher risks of diseases, such as cancer. So with one easy fix — pun intended — you can avoid all these problems and responsibly house your male and female pets together.

Next: This duo would work best if you give it a few years.

14. Many small children and pets

girl and puppy

Some young children don’t understand safe behavior around pets. | iStock.com/Petrenkod

Remember that Minute Maid commercial where the little boy almost pours juice into the fish tank? His dad probably was far too calm about that near fish massacre. Small children and animals are difficult to mix.

Kids just don’t understand the proper handling of pets. Some children might be too rough with a pet, causing injury to the animal. But on the flip side, a child’s unpredictable behavior might cause an animal to react dangerously, possibly injuring the kid. Either way, until your child is old enough to understand how to treat your pets, you’re better off keeping them apart (or highly supervised).

How to make it work

A group of domestic pets, including a puppy, parrot, rabbit, cat, and a baby chicken all sitting together

As long as you play it safe, you still might be able to have more than one type of pet. | iStock.com/Adogslifephoto

We didn’t want this all to be bad news because we love interspecies friendships. It’s possible to house more than one species if you’re willing to put in the work making sure everyone is safe.

Because animals are unpredictable, the real key is management and never getting too comfortable. Pets who have the capability to harm each other should never be trusted together, even if you’ve never had any problems with them. It just takes one random swipe of a claw — intentional or not — to cause serious devastation. Always supervise pets that could hurt each other when they’re together, and make sure they’re completely separate when you’re not able to watch them.

Read More: Celebrities Own Some of the Most Exotic Animals As Pets