Most often, the question when it comes to pets is: "I have a _______. Can my hedgehog and my _______ have play time together?"

Most often, the answer is: No.

Hedgehogs may have quills to protect them from predators and the other pet may be domestic to you, but most of them are still predators to the little hedgehog and are usually much bigger than the hedgie. Cats and dogs, for the most part, should be kept away from hedgehogs. The only exception to this is if it's a very passive, non-excitable animal. Then introduction may be a possibility. You have to examine, though: is this going to benefit the hedgehog in any way or is it just for your amusement?  In most cases, it doesn't benefit either animal.  

When it comes to introduction, puppies are definitely a no-no. Some people have successfully introduced hedgies and dogs, however they've always been older laid back dogs--not easily excitable puppies. Most of the time, after the initial introduction, the dogs ran away and wanted nothing more to do with the hedgie. There are only one or two out of the bunch that don't mind having the hedgie lay on them and hang out with them--they were the exceptions, not the rules. In most cases, neither gets anything out of the deal.

Ferrets are definitely a no-no also. They are rough and love to play, and your hedgehog could easily be injured during play time with a ferret.

NOTE: Ferrets actually should not be kept in the same area as a hedgehog in general.  Avoid housing them in the same room.  If a hedgehog smells a ferret, it feels threatened because of that predator being around, and will not be comfortable inside its cage because it doesn't know the predator can't reach it.  It's best to keep them totally separated, preferably on opposite sides of a home.

Other hedgehogs for playtime are also an issue. Males will often fight each other, resulting in a bloody mess that will make you wish you'd never introduced them. Males and females will mate and your female could end up pregnant--which could kill her if she's never been bred before and is above breeding age. Females, too, will sometimes fight. Unless you intend to breed, it's generally not a good idea to put two hedgehogs together. There is no need; I would not do it.

In some cases, size and predatory instincts are the issues; in other cases, diseases are. Chinchillas, guinea pigs, hamsters, etc should not have interaction time with your hedgehog because communicable diseases are easily spread and there's no benefit of putting them together, anyway.  In instances of smaller animals, just don't do it.

Even a pet that has spent time with the hedgie many times with no problem could still have predatory instinct kicking in at any minute. Because of this: It is very important that you never leave your hedgehog and another pet alone!

There have been instances of cats that have played with hedgehogs for years with no problem suddenly deciding that the hedgie is something to attack.  Even with the quick reflexes a hedgehog has, one swat of a paw can get past and do a lot of damage before the hedgie has time to ball up, especially in an unexpected attack.

If you still think you need to introduce the two, there are a few things you need to do to make sure your pets are safe.
- Introduce them on neutral territory. If your other pet has a room in the house they are very territorial about, like the room it sleeps in, take them somewhere else in the house to introduce.
- NEVER put the hedgie directly down in front of the other animal. Hold the hedgie firmly between your hands and allow the other pet to sniff the hedgie from a little distance. This way you can quickly get the hedgie out of the way if the other animal were to decide to attack. After a nose full of quills, most cats/dogs will likely not feel the need to bother again, but better safe than sorry.
- If you decide it's safe and you put your hedgehog down for actual interaction time, be on guard. Be prepared to intervene if there is the slightest sign of aggression, or if any rough-housing becomes involved.
- Even if all goes well, you should always supervise playtime and NEVER leave the two alone. If you have to leave the room for a minute, your hedgehog goes with you--NO MATTER WHAT. It only takes a second for a tragedy to happen.

For the record, I do not recommend that any pets meet or have playtime with a hedgehog. The hedgehog is a solitary creature and will not likely get any pleasure from meeting another animal. There is not really a good reason to have them meet. Others may feel differently, however, and the above information is provided for a little guidance to those people.

One big golden rule when it comes to other pets:

ALWAYS keep the hedgehog's cage in an area where no other animals can get to it!

Quentin  has a cage that is two Sterlite bins connected by PVC pipe.  Normally it sits on a small table, elevated off the floor.  One day my boyfriend was watching him in another room while I cleaned the cage.  I went out to get something and when I came back I forgot to close the door to the room.  I also have a cat.  I took the cage apart and had half sitting on the floor while I cleaned the other part.  The cat came in while I was cleaning and jumped into the unsupervised part.  I turn around to find her wedged in sideways (for some odd reason) chowing down out of the food bowl.  Of course it was cute while I was cleaning and my hedgie wasn't in there--but if the cage had been together and had been up on the table, odds are she would have knocked it over and completely off the table.  My hedgehog could seriously have been injured, as could have the cat.

For the safety of both your hedgehog and your other pet, please keep the cage in a room to which that the other animal(s) do NOT have access.