Does your dog shake when sleeping? Does it worry you? There can be several reasons for this shaking but they’re usually not indicative of something seriously wrong with your dog just because it shakes when asleep.

When a dog shakes while it’s sleeping it can be alarming because you can’t be sure what’s causing the shaking and whether it’s a natural occurrence, or if the dog may be in pain. When your dog is deep in REM sleep you may notice it shaking, crying, kicking, or moving its legs like it’s running.

Rapid eye movement (REM) is the sleep stage in which dreams happen. During REM a dog’s mind is fully active and aware, even though its body is in a completely calm state. The dog’s mind will replay images from events that happened that day or even past events, and its body will react to those images, causing involuntary movement during sleep. There have been many studies proving that dogs do experience REM sleep stage.

It is interesting that larger dog breeds don’t have dreams as frequently as do smaller dog breeds. If dreams are the reason for your dog’s actions, then you have nothing to be worried about.

If you notice these same movements occurring frequently when your dog is simply resting, it’s possible that your dog is having an epileptic seizure. Epileptic seizures stem from a disorder of the nerve cells in the dog’s brain and generally occur during consciousness but result in the dog losing consciousness. Nerve structures in the brain produce electrochemical signals and carry them to the brain where instructions to perform the various functions of the body are regulated. When these signals become scrambled, the result is an epileptic seizure.

During an epileptic seizure a dog may bite, snap or jerk, hurting its owner or itself. Since epileptic seizures cause unconsciousness, the dog will have no recollection of this behavior. Epileptic seizures do not seem to be controllable and tend to recur over the life of a dog.

There are other causes for seizures in dogs such as tumors, kidney and liver disorders, infections, brain damage and toxins. A low oxygen level in the blood or blood glucose levels that are too high can also cause seizures. A dog might have a partial seizure affecting only parts of its body or a generalized seizure called a grand mal that affects the entire body. Grand mal is the most severe type of seizure.

Although not very common, tremors in dogs can also be caused by abnormal cardiac contractions and restricted blood flow within the heart. This results in erratic involuntary movements. If this occurs while the dog is sleeping or awake, you should ask your veterinarian to give your dog a complete medical examination.