One of the conditions which sometimes affects Harriers is often not seen as a health condition, but rather a behavioral problem: genetic shyness. Lately, however, there has been an increase in the debate concerning whether or not shyness in dogs is entirely dictated by environment, or whether there is a genetic predisposition in some dogs, or even some breeds, to become shy; this is the whole nature versus nurture debate. Indeed, many scientists are now claiming that shyness does have a genetic component and it may be inherited.

In the past, it was automatic to assume that any dog who demonstrated shyness had been abused some time in his past. This certainly happens, and shy dogs may have a variety of traumatic experiences in their pasts, but this is by no means the case for all shy dogs. There are a number of shy dogs who have had loving homes from the beginning and yet exhibit some of the signs of shyness; there are also many dogs who have been abused and have never exhibited shyness. Experts have put forth the theory that if a dog is already predisposed to shyness, an abusive or otherwise negative environment will exacerbate that shyness, bringing out symptoms that perhaps were not previously present.

Even if you are not planning on abusing your Harrier, you must remember to give him a structured environment and not do anything that may lead to the dog's feeling threatened or excessively uncomfortable. Perhaps the main factor leading to exacerbation of genetic shyness is a lack of socialization; socialization must start when dogs are small puppies and continue throughout their entire lives. Without socialization, any small tendency towards shyness will develop into extreme fearfulness and possibly even aggression. If a puppy's mother is shy, she can pass on the shyness to her offspring, both through her genes and through her actual behavior; puppies often model their mothers. In other cases, the genetic component of shyness is so great that a dog will develop shyness with no other factors present.

There are certain signs that indicate shyness in dogs, which can either involve the dog wanting to run away from or attack a perceived threat. The dog may have his ears flat against his head, or he may pant strangely. Shy dogs can often be observed with their tails between their legs and crouching; they often also urinate at inappropriate times. Shy dogs often have dilated pupils and shake for no apparent reason. If you notice your dog exhibiting any of these behaviors, you should take him to the vet, who will first attempt to rule out any medical conditions that could lead to the appearance of shyness. If your dog is experiencing hip dysplasia, problems with his spine, vision problems, an ear infection, chronic pain, or a number of other conditions, he could become nervous. If your dog is healthy in all other aspects, then you should focus your attention on training approaches that will gradually improve his behavior.