Can Cat and Chinchilla exist together?    

Ø  Cat and chinchillas can coexist peacefully in the same household under some circumstances. If you already have a cat, you must carefully consider the personality of the cat. Many people do have cats and chinchillas, but it works best with mellow cats that don't care much about the chinchilla. 

Ø  If your cat is an active hunter, bringing in a chinchilla may not work out well. Even when the chinchilla is in the cage, a determined cat could frighten a chinchilla by reaching through the cage bars or even just staring at the chinchilla. After all, chinchillas are rodents and a cat that likes to hunt is likely to consider your chinchilla fair prey.

Ø  If your cat is more laid back or mellow, or doesn't care much for hunting, then you have a lot better chance of the cat pretty much ignoring the chinchilla, and the chinchilla will likely get used to the cats presence and not be overly stressed. If a cat touches a chinchilla and softly grips, the chinchilla's fur will release and eventually can go bald. Also if there’s a cat around he may become stressed and start biting himself.     

Ø  Have close supervision of cats around the cage (of chinchilla) for the first time until it can be determined that the cat isn't going to go after the chinchilla. When the chinchilla has free time out of the cage, the cat should be put in another room or restrained (at least for the first while). And, even with the mellowest of cats, never leave a chinchilla out of the cage unsupervised with a cat.    

Ø  Of course, if you have the space and time, you can make it work even with a hunting cat by always keeping the chinchilla and cat separated (obviously, this requires a lot more care and juggling of pets' needs).    

The chinchilla will need a safe cage and a room where the cats can be locked out of while you aren't home. That way there's no risk of your cat attacking the chinchilla. The cats could be allowed in the room when you are there and they may actually get used to each other. However if the chinchilla is afraid of the cats then it could actually attack them! Some cats are quite shy and may not fight back against a chinchilla. That means they could get seriously injured as rodent bites can be very deep and nasty.  

However each cat is different and it really depends on the individual. Some cats have a strong prey drive, others can't be bothered. You can sort of "test" your cats and how strong their prey drive is by playing them with a feathered wand toy. Of course they're going to be interested in it, but the question is just *how* interested. If they pounce and grab at it with great interest, and seem bent on killing it, then their prey drive is strong and they may make the chinchilla's life very stressful.  

your best bet is to start with a kitten, so that he or she can be brought up with the chinchilla. This way the predatory instincts toward the chin are less likely to develop.   

Some chinchillas are completely ok with sharing a house with cats and some aren't. There isn't any way to predict how a particular chinchilla will react. They never should have contact as there is bacteria in some cats saliva that can cause a fatal pneumonia in chinchillas. And no, we don't know that "sometimes doors get left open". If you can't be completely responsible for the safety and well being of caged animals, you need to not get them.