Here is a good "course" on self defense sprays.

http://www.galls.com/DefSpray1.html

In Canada, bear sprays are legal if they conform to Canadian standards. I believe they must be large enough so they can not be easily hidden.

The best sprays are a sticky spray, about the viscosity of honey, that does not disperse easily in mild winds. Not all sprays available in the US are allowed in Canada. We have had no problems carrying sprays into Canada as the bear spray we carry was purchased in Canada.

We consider dogs to be the most dangerous animal we are likely to encounter. I worked for a time in a hospital Emergency Room. Dog bites are common and do serious damage. I have seen a childs head pierced by the teeth of a family pet (child died). Witnesses say the dog just walked over to the child and clamped down on the kids head.

In another, much studied incident, a dog attacked a man on the street without warning. The owner, a large male, was unable to physically restrain the dog. After a great deal of investigation the following was discovered.

The dog was put inside everyday while the owners went to work. Once a week, a garbage man entered the back yard (the dogs domain), made a lot of noise and took something (the smelly garbage). Neighbors said that the dog always "went nuts", barking and banging against the door, whenever the garbage man came.

The man that was attacked looked a lot like the garbage man.

Never trust any dog. You just don't know what is going on in "dog world".