In wild animals, the arousal level is constantly regulated in order to conserve vital energy that might be wasted gearing up for an unnecessary reaction. The animal is not easily aroused by unimportant events, and has mechanisms (such as “shaking it off”) to physically release the charges as they occur in the body and so regulate the level of arousal in the nervous system. But humans have tinkered with this system by breeding dogs selectively for different behaviors. We made critical changes to the nervous systems of different kinds of dogs, desiring weaker responses to some things and stronger responses to others.

Bull dogs have been carefully selected for a uniquely delineated set of responses on a neurological level. The people who bred these dogs did not want them to waste energy reacting to the little things. A dog who idled very low for much of the time—far from hyperactive—was ideal. Ironically, the low-arousal genetic stage of the guardian breeds was the perfect base for such a dog, willing as these protectors were to conserve their energy for the moment in which an action was required. When breeding for a bull dog, however, people still desired the conservation of energy but wanted a dog who could then engage more quickly to a very high level of arousal when the moment finally arrived. Breeders succeeded in creating just that: a high-arousal dog who could be easily moved from steady quietude into a suddenly charged “zone” (aggression).

English Bull Dog

To those on the outside of this neurological explanation, it may look like these dogs just unpredictably change into some “red zone” when, in fact, they are actually just high-arousal animals responding pretty predictably to an escalated circumstance and a heated atmosphere. It’s not rocket science to stay out of trouble with a bull dog. As long as you keep it chill and copacetic, your bull dog can be cool as a cucumber all day long.