Hi Clare,

Thanks for your question.

I know that it is impossible for me to be certain of this but I want to say that I’m certain your dog is not having nightmares. I think there is a much more reasonable explanation than that.

I have seen this behavior many times. When a dog growls and bites when woken up it often occurs because the dog is older and their senses, like hearing, smell and sight are deficient, so they are easily surprised upon waking. It’s a truly common issue. This assumption is greatly supported by the fact that you also describe how she gets aggressive during play. I’ll make the assumption that this is a new development as well the way you describe it.

So what do we do about it? First of all, it’s important to understand that you have provided extremely little information your question and I cannot be confident about any of my assumptions. My recommendation is that you visit your veterinarian for a physical exam and consultation and have them perform wellness testing. Whenever we see a behavior change in a dog, we need to rule out the influence of a disease process. For example, if she has arthritis, dental pain, or a condition that can change her cognitive function, it could cause a more aggressive attitude. There are metabolic conditions that have been linked to aggression in a dog such as hypothyroidism. So it is important that you determine whether or not there is a treatable condition here before assuming that it is simply a trivial issue like nightmares or spontaneous aggression where it didn’t exist before.

Aside from medical conditions, which I recommend you assess first, it’s common for dogs to be aggressive when they are awoken suddenly and they have reduced auditory capability. So if she is of a geriatric age, I would recommend you don’t wake her up when you’re within reaching distance of her. Consider stomping your feet a reasonable distance away so that she may feel the vibrations of that instead of touching her/shaking her awake. As our pets age, their sense can diminish and it makes the world a scarier place. They are more easily surprised and can react negatively. So be aware of this and adjust accordingly.

I hope this helps.

Dr. Clayton Greenway