Why do dogs walk around in a circle before lying down?

Circling is innate behaviour

The most probable reason why many dogs circle before they lie down is that their ancestors did so in the wild. You just can’t beat a good nights sleep and simply by circling  around in an area of grass would create a more level, softer surface for lying on. If the area was covered in snow or leaves, circling would similarly soften and level the spot.

Once the area is as level and soft as the dog can make it, they might just do a little digging in the center. Making a shallow pit to lie in can keep an outdoor dog cooler or warmer depending on the weather and time of year.

When circling behaviour is worrisome

While circling and doing a little digging before settling in for a nap is normal behaviour for many dogs, there are times when this behaviour may indicate a medical problem.

If circling is new behaviour in an older dog, there may be some discomfort causing it. Sore joints, a painful abdomen, or back pain can cause a dog to be reluctant to lie down, resulting in restless circling or getting back up immediately after lying down.

If a dogs circling seems compulsive and is not confined to the time period just before your dog lies down, a neurological problem might be the cause.

If the circling is accompanied by a tilted head or vomiting, it could indicate vestibular disease or a neurologic issue.

In any of the above situations, you should take your dog to the veterinarian immediately.