Our dog snaps and bites.

Our dog is a year old and lately his behavior has gotten bad. ( probably not the right word, but I can't think of another ) He is usually fun, playful and loving and protective.
Here are the changes I have noticed some of which I attribute to human behavior and have tried to stop.
When people that he knows ( family in the home included ) he will often snap and sometimes nip. * Sometimes but not always I see people move in too fast and come in overhand and I think it startles him. When that happens I blame them, not my dog. But more often that anything, they may sit down, they gently try to pet him and sometimes just stand up to walk away and he will snap and has been known to charge and nip. He is very protective of my wife, he will curl up on her lap on the couch and if anybody gets near he growls and lunges if they don't back off. He just bit my 5-year-old for trying to give her mommy a hug before bed. I need advice on how to stop this behavior, we love this dog but our kids safety is first. A friend says getting him neutered will stop it all and I hope he is correct because we are setting the appointment. But in case it don't, what else can I do?
He is a chihuahua/dachshund mix if that matters.

I don't think neutering will stop this behaviour. He has by the sounds of things been allowed to guard your wife. He is still young I think you need to start retraining and setting some boundaries for him. Keeping him off the furniture till invited and maybe a baby gate if you are able to put one somewhere so he can be separated from your wife and children while your children have time with their mum.
Also a vet check may be in order to make sure he has no underlying pain or trouble with his sight as it sounds like he is being startled by movement.

He is at the teenage stage, generally smaller dogs come out of it earlier than bigger dogs so hopefully he will soon be out of it. Like all teenagers they test the boundaries but there is more than that here.

Has he ever growled when someone went to stroke him? To a dog a hand going over the top of them, mainly to stroke the head, is an aggressive act to a dog because the back of the head and neck is a very vulnerable place for a dog, we have to teach them that we are not trying to kill them when we go to touch those places. This is often made worse if the hand is moving fast. When we have a dog from a young pup they learn this without us really teaching them.

First neutering won't stop this behaviour and may make it worse, from what you say he seems to be a nervous, stressed dog and neutering will make it worse if he is. At the moment I would hold off on having him neutered, I made the mistake of getting a dog like him neutered and regretted it.

With a dog like him we need to use our brains to get round this behaviour, does your wife do most things for him like feeding, training and walking him? If she does can you take some if not all, of this over?

He is a very small dog, Chihuahua and dachshund often have problems because to them we are massive, if you get down on the floor, have your head at his head and get people to walk past close to you and pat you on the head it will give you a better understanding of what he sees and feels. It was a big shock to me when I did it for a small dog I had just taken , I was terrified If nobody understands why you are telling them to do something then get them to do the same.

Your 5 year old needs mum time, use baby gates to help with this and give your dog something to do on the other side of the gate. He can have his meal in a Kong, seal the Kong with peanut butter or cream cheese then freeze it, it will take longer for your dog to eat it which will give more time for your child to have mum time.

Your child also needs to be taught not to go near your dog when he is asleep or eating, that is a really good time to get bitten. If your dog growls your child needs to move away, growling isn't aggression it is communication, your dog is telling you he is not happy with what is happening and should be listened to. The more you listen to him the more confidence he will get with you and allow you to do more.

Dogs should be left alone to eat in peace, you can be in the same room as him but leave him alone until he has finished and moved away. A lot of owners think that putting their hand in a dog's food bowl or taking the food away when eating will teach him not to protect it, what they are doing is teaching the dog that he has a reason to protect his food and you can get bitten. I have taken of quite a few dogs that would bite if I went near his food, by leaving them alone they gained confidence in me and if it became necessary for me to move their food I was able to.

I often see people carrying small dogs, I never understand why they do but many dogs don't like it and only tolerate it so no picking the dog up, it is easier to pick him up instead of training him but not for the dog. Teach him to be obedient, to get off the furniture when you ask him to, that is really easy to do. He needs to sit and down on command as well as have a good recall. If you need more information on these just ask but better to find a good training class were they use positive methods only.

Good luck with your dog, I am sure you can work all this out, you will find the dog learns a lot quicker than the humans do which is why I always tell people to get down to their level, life takes on a different meaning then.

I highly doubt he is protecting your wife, he is resource guarding her since he believes she belongs to him and only him. Implementing NILF would be a good pace to start. By avoiding situations where he is most likely to snap and bite, like siting in your wife's lap, will give an opportunity to teach proper behaviours. I don't understand why people think neutering is a miracle cure. Neutering simply cuts off proper hormone production if done too early and interferes with hormonal maturation in a physiological sense. It has noting to do with a behaviour problem such a resource guarding.

All the best.

NIL is old school training, it has caused a lot of problems, it does teach the owner how to be consistant which is rearly important. From what has been said everyone works differently with the dog so he is confused, stressed and insecure.

Regards NILF, I hadn't realised this was old school training. I thought it was a technique that Dr Ian Dunbar has suggested.

I must admit I cannot make my boy sit and wait for his dinner. He does have to do something to get treats though - they're never freely given.

Back to the op, I think all the advice given so far has been very good and have nothing to add, except I would get the whole family involved in training, training, training and more training. I would get this little dog up to about 20 mins of training per day (in 5 min chunks), just basic sit, stays, downs etc, get him to exercise his brain, teach him some tricks - figure 8s around some cones. I wasn't able to see the point in this kind of training but boy do I see it now. My dog has to have this training everyday (well 5 out of 7), lots of clicker training.

Is that meant to say 'rarely' or 'really'?

In the context it is in I'd say it was meant to be REALLY

I hadn't heard of NILF training, but just googled it. On the surface sounds fine - reward and punishment. What's wrong with that?

I do personally like some of the ideas of 'nothing in life is free' training. The main point being that the dog learns that he/she needs to listen to get the reward. My only use of punishment would be to not give eg. when feeding asking the dog to lay down on his/her bed and wait patiently. Of course this needs to be a dog who knows wait and knows go to bed. If the dog gets up before being asked send it back. Same sort of thing for treats, attention, play, cuddles, getting up on bed ect.
Most dogs I meet automatically sit and look at you when you have a treat they want. My dog will fetch a toy and then lay down next to me to ask me to play, he doesn't pester he just looks back and forth and if I don't respond he either plays by himself or waits (usually falls asleep).
Am I missing something????