Ticks are fairly common ectoparasites of dogs (and cats). How often you see ticks on your dog and how severe a tick assault will be depends on the region of the country in which you live, the time of year (tick activity varies in warm and cool weather), the habits of your dog, and how and when you use tick control products. Some ticks can infest dogs that spend most of their time indoors, and even dogs that only spend brief periods of time outside can have ticks.