Why Do Dogs Shake?

An unusual encounter with a middle aged Terrier back in the Summer of 1998 gave me an interesting insight into the dog body language of shaking / or shivering dogs. I set my gaze on this small, but friendly dog and observed as she stood shaking, as if petrified or very cold.

At first glance, it was my assumption that the dog was extremely nervous about something. But no. As I got to know the dog better, a more confident and bold animal you would struggle to meet. So why was she shaking? James Hunt explores more...

Stress is a complicated emotion. It can manifest itself in many different forms. I've sometimes caught my legs shaking furiously as I've sat in my seat on a warm day at a football match. Nerves, anxiety, call it what you will, my sub-conscious display of what can only be described as stress body language would indicate I might be a nervous person. But it's not that simple, is it?

Why Do Dogs Shake?

I happened to be shaking at a particular time under a particular circumstance but this stress behaviour would not be applicable to my more general personality. So when we come to the question of why dog dogs shake, we must delve a little deeper.

What The Studies Of A Dog's Nervous System Have To Tell Us About Why Dogs Shake

Dogs of any breed, size or type can suffer from stress. In fact, a certain amount of stress is necessary for a healthy life. Hunger begets a form of stress that motivates us to find food, a healthful activity. However, a pet dog that receives a doting owner's petting and praise on demand all weekend tends to build an insatiable "appetite" for constant social gratification.

Later, left alone on weekdays, the dog is frustrated by an unsolvable, hence frustrating, problem: it cannot find its “emotional food”. Whether this condition results in problem behaviour depends on the stability of the dog's nervous system and how the animal behaves to relieve tensions that will always arise from frustration. For example, a chewing problem develops in the orally oriented animal. The tension relief is manifested by chewing up objects that smell and taste of the owner, or things that, to the dog, are symbolic of the owners.

Developmental Neurophysiology and Behaviour

Each puppy is born with and develops a nervous system that is unique in many ways. Both genetic and environmental factors produce these individual variations. Some important developmental yardsticks may be applied to the canine nervous system to explain many kinds of behaviour.

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Why Do Dogs Shake?

Turnover of RNA (ribonucleic acid, a vital chemical messenger in the memory process) in a pup's brain does not reach adult rates until 22 weeks of age. This helps explain why a puppy may have "accidents" during its house-training program, or why training pups to simple "Come," "Sit" or "Stay" commands is best conducted in brief sessions no longer than 5 minutes. This may also bear on the 13 to 16-week-old pup's behaviour, when it apparently does not recognize, growls at, or runs from visitors with whom it had friendly previous contact or a pup who starts barking at objects previously ignored. In this case, the optic tract also may not have reached maturity.

Why Do Dogs Shake?

Mammals normally born blind but reared without light until maturity develop apparently normal eyes that are "nerve blind" due to failure of the optic tract to develop normally - a good reason not to shake puppies as punishment. Stimulus deprivation of various sorts produces animals with comparatively lighter and less precisely structured brains, according to Russian studies in the 1950s.

Puppies drastically restricted from sensory stimulation and exercise in special cages from weaning until maturity failed to avoid painful burns on their noses from matches or pin pricks, while normally raised puppies quickly learned to avoid them. The deprived pups appeared to feel the pain, but did not learn to associate it with the match or the pin. Even more bizarre, these deprived puppies spent more time close to the human experimenter after being burned or pricked than before the painful stimulus. This was not the case with normally reared puppies.

This work may explain why so many behavioural problems are experienced with puppies bred and reared in the restrictive environments of "puppy mills," where litters are reared in stacked cages and then shipped to pet shops, where they spend more time in cages.

Shaking, in particular, could be the physical manifestation of:

  • Fear
  • Nerves
  • Extreme or mild stress
  • Anger
  • Rage
  • Reaction to cold temperature
  • Excitement
  • Mental stimulation
  • An attempt to loosen muscles or relieve minor discomfort from a minor physical impact
  • Simply attempting to shake out water or debris from coat

It is known that tremoring and shaking can be common physical traits in smaller breed dogs. However, the reasons as to why this is the case appears to have baffled vets and behaviour experts for now.

Like the small Terrier I met in 1998, the dog was shaking to a point that a neutral observer would conclude she was very upset or stressed about something. It was only upon further inspection and getting to know the dog that it became apparent she displayed none of the usual traits associated with fear, anxiety, nerves or even extreme excitement.

Of course, I asked the dog's owner; why does your dog shake like that?

His reply; "oh, that's just something she's always done. When she is thinking, she tends to shake."

Do dogs shake because, for some of them anyway, 'that's just something they do?"

Could that really be an adequate explanation for this particular display of dog body language?

Well, adequate it most certainly isn't, but it does perhaps give some comfort to owners of dogs that shake for no apparent reason. It may well be the case that there is no specific behavioural or mental reason why certain dogs shake. It certainly isn't always the case that a dog is fearful, cold or even excited about something.

In more serious cases, shaking could be the sign of illness, including Distemper. But for a dog who seems to shake at random times and has done so from an early age, it is much more likely to be 'something they just do'. You must forgive me for my frustration at not being able to get to the scientific bottom of answering the question of why do dogs shake. "Dogs shake because it's just something some of them do" leaves me - almost - shaking with disappointment.

From the vets and behaviour experts I have asked this question of, the most common consensus has been that shaking is most often as a result of a build up of energy rather than fear or indeed reaction to cold.


  1. I read this article with interest as my 9 year old border collie x sometimes displays mild shaking. This usually occurs when waiting to go out to drop him at my parents’ on my way to work. Having already had his morning walk it wouldn’t appear to be excitement, he isn’t afraid of getting in the car and enjoys his time in ‘day care’ so it is confusing as to the cause of his shakes.

    On another point, just where on earth have people been burned and pricked with pins in the name of ‘research’. I find this very disturbing!!

  2. Apologies – my previous comment meant to read ‘where on earth have puppies been burned and pricked with pins’ not people!!!

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