genetic changes that often lead to the expression (or change the intensity) of certain behaviors, given an environment that supports that behavior. For instance, the border collie, often used and bred as a herding dog, performs behaviors like showing “eye” (fixing one’s gaze at an animal), “stalking” (creeping toward the animal while maintaining eye), and chasing (Coppinger and Schneider 1995). A dog's predisposition to these actions can be molded, with training, into sheep‐herding behavior. Other examples of breed tendencies abound: the pointer's tendency to “point” with his body toward game; the retriever's ability to fetch and retrieve game in water or on land; a hound's vocalizations while tracking an animal with his nose; and coursing dogs' running pursuit of game.
In J. P. Scott and J. L. Fuller's classic longitudinal studies of five breeds of dogs (sheltie, cocker spaniel, basenji, beagle, and fox terrier), they noticed distinct differences between the breeds on scales of emotional reactivity, trainability, problem‐solving behavior, and other capacities (Scott and Fuller 1965). Subsequent studies continue to identify breed‐based heritability of complex behavioral traits (MacLean et al. 2019). For instance, golden retrievers tend to rank highly on trainability, while the beagle ranks low; huskies rank low on attention‐seeking, while dachshunds and toy poodles rank high (Serpell and Duffy 2014). At the same time, variance within breed is also observed (Mehrkam and Wynne 2014). A study of impulsiveness—the inability to inhibit behavior in the presence of particular cues—found differences between breeds but also within breed, particularly according to working, show, or pet lines (Fadel et al. 2016). While dog behavioral traits may have genetic influences, neither breed nor genetics will predict an individual dog’s behavior.
For contemporary dogs who are not employed as working dogs, their behavioral tendencies may be more problematic than functional. For instance, a border collie without sheep to herd may take to stalking and chasing bicyclists and small children who are running. Pursuit of and nipping at the motion of feet in the dog’s vicinity is typically an undesired behavior and may even be perceived as “aggressive.” A guard dog's barking at legitimate guests may be considered inappropriately “dominant” or “territorial.” Owners may wield ill‐suited measures to try to fend off this perceived threat to their authority (Herron et al. 2009). In both cases, the tendencies that humans have bred into the dogs are recharacterized as “misbehavior” in a companion‐dog context. Giving a new owner some understanding of the breed tendencies of a dog will assist the owner in working appropriately with what could otherwise be considered puzzling or disturbing dog behavior at home.
1.6.2 Spay and Neuter and Behavior
Sterilization—spaying and neutering, or de‐sexing—is currently well established as normal, even preferable, for owned domestic dogs in the United States. Animal protection groups and humane societies advocate dog sterilization, and it is required for dog adoption from many animal shelters. A common argument for sterilization is that it improves the welfare of the individual animal. Another ostensible benefit of sterilization is reducing the population of unwanted animals; however, published evidence of the degree of such benefit in reducing intake of shelter dogs is limited (Urfer and Kaeberlein 2019).
While state laws and advocacy groups often tout behavioral improvements that result from sterilization, such as reduced roaming behavior, reduced aggression, and fewer unwanted sexual behaviors, including mounting (Horowitz 2019), research is conflicting as to these claims. Studies gauging levels of aggression by male dogs, for instance, have found variously that aggression either decreased, remained at the same level, or even increased after neutering (Bain 2020). What is clear is that sterilized dogs have been “deprived of the ability to perform one of the most fundamental natural behaviours” (Rooney and Bradshaw 2014), which, with the health and behavioral effects still debated, may most robustly reflect a cultural aversion to canine sexual practices (Horowitz 2014). Similarly, it is also clear that early removal of the source of gonadal hormones has repercussions beyond the sexual: the hormones are implicated in functions as varied as bone growth, maintaining muscle mass, and learning and memory (Horowitz 2019). Ideally, considerations about sterilization should take into account the breed, age, and sex of the dog as well as the owner’s circumstances and expectations for the dog. See Chapter 4 for further discussion of the physical and behavioral health impacts of spay and neuter.
1.6.3 Shelter Environment
Shelters can be characterized as novel environments, and while less neophobic than their wild relatives, novelty in its many forms can still act as a stressor for dogs. To support dog well‐being, shelters increasingly consider individual dog perception of the shelter and use available resources to identify and address challenges posed by new sights, social encounters (both with conspecifics and people), “loud” smells and sounds, and general unpredictability.
1.6.3.1 Age
Puppies may be particularly challenged if there is an inundation of sensory information and lack of socialization opportunities that prepare for later‐in‐life experiences. Shelters can consider dam and littermate contact, prioritize early life socialization experiences, and explore real‐world housing opportunities outside the shelter. Many dogs entering shelters are between one and three years of age and in the midst of social maturity; these dogs would benefit from many of the early life socialization considerations that younger dogs are afforded (Hammerle et al. 2015). Senior dogs may have difficulty coping with separation from an attachment figure as well as novelty. Considering behavioral differences between normal aging and cognitive dysfunction, as discussed earlier, would greatly assist this population. While collecting information on owner‐relinquished dogs is valuable—for example, through owner report or behavior observation—so too is not over speculating about a dog’s past or future. Owner reports do not always correlate with observed behaviors in shelters or subsequent homes (Stephen and Ledger 2007), and behavior may be modifiable.
1.6.3.2 Prior Kenneling
Prior experiences can affect dog perception of the shelter. Dogs with prior kenneling or sheltering showed a less‐activated stress response when introduced to a new kennel environment, while dogs without showed elevated cortisol levels (Rooney et al. 2007). Similarly, dogs relinquished from homes who had not had prior exposure to a shelter showed an increased physiological stress response without adaptation during the first week; meanwhile, dogs marked as strays and returns showed a decreased physiological stress response during that time (Hiby et al. 2006). At the same time, length of stay, coupled with behavior issues—either from before or during a dog’s shelter stay—can contribute to chronic stress and diminished well‐being.
1.6.3.3 People
Numerous studies find that the mere presence of a human can buffer a dog’s stress response to the innate challenges of the shelter environment, yet differences between dogs are also observed (Hennessy et al. 2020). Owner‐relinquished dogs—who may be separated from a figure of attachment and lose social stability and predictability—may be particularly challenged; while petting interactions as short as 15 minutes have the potential to reduce physiological stress levels, this reduction was observed in strays, not owner‐relinquished dogs (Willen et al. 2017). Additionally, peoples’ individual characteristics as well as the nature of the interaction can affect dogs. Some studies find that dogs show more comfort with people who are identified as women than men. Hennessy et al. (1998) found that when men spoke more quietly and petted in a more soothing way, men were as effective as women in maintaining lower dog stress levels. All dog lovers entering shelters should remember that each dog has his own past experiences and may perceive new people as unfamiliar or be wary of their personal characteristics. Considering how physical contact may be interpreted by the dog, allowing dogs to initiate contact and prioritizing
