THESIS: An Investigation Into Gender-Specific Fear Of People In Canines


By Hannah Walker

In this paper Hannah Walker investigates the gender-specific fear of humans that some dogs experience.


The entire paper is available to view below.

Dalmation dog looking away

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Although dogs in general do not show a bias towards one gender, it is often anecdotally-reported that dogs, particularly rescue dogs, more frequently show discomfort or hostility towards unfamiliar men than women. The dogs’ owners may assume that the cause of their dog’s fear or aggression around men must convey that the dog has had a negative experience with men in the past, especially particularly when the dog only fears specific types of men, such as those with beards, sticks or hats. However, fear of unfamiliar men is common amongst anxious dogs, even when there is no history of trauma or abuse. Due to differing attitudes and practices between the sexes, dogs of indeterminate backgrounds are statistically more likely to have had a negative experience with men than women. However, there are also many olfactory, visual, auditory, developmental, genetic and circumstantial reasons that can have significant influence on how dogs perceive people. All dogs and people are individuals and there are no steadfast rules dictating whether a dog will be more or less receptive towards a specific type of human, but gender-associated characteristics and past experience do have an effect. This thesis will explore the many different factors that can contribute to gender-specific fear of people in dogs.

Many people who work with or own dogs will be aware that they are more likely to show hostile or fearful behaviour towards an unfamiliar human if they are male than if they are female [Hennessy et al., 1997]. As would be expected, fear of men is particularly prevalent in dogs who have suffered from poor socialisation or development and as such, rescue dogs commonly display reactivity or avoidance behaviour towards male humans. Multiple studies of shelter dogs document that high proportions of kennelled rescue dogs are reluctant to approach or interact with men [Lore & Eisenberg, 1986] or show increased barking and aggressive behaviour towards men. Conversely, women more commonly induced more relaxed postures and behaviour in the same dogs [Wells & Hepper, 1998]. This trend is not exclusive to shelter and rescued dogs, however; a study conducted on working dogs found that most of the dogs who failed during the training and qualification processes did so due to fear of humans, which was almost always specific. Most of the failed dogs feared men, but others were specific to children or strangers. None of the dogs, however, had displayed specific fear towards women [Gunrow, 1995]. The dogs in the study had all been raised from puppies and, thus, efforts had been made to ensure their developmental environments were adequate. Therefore, although poor socialisation and development do influence the likelihood of the development of man-directed fear or aggression in dogs, it cannot be the only factor. This is unsurprising, considering that the domestic dog resulted from co-evolution with humans over thousands of years and, as a result, they are influenced by many different aspects of human behaviour [Payne et al., 2015]. Human understanding of the world through the eyes of the dog is still rather limited, but we have begun to scratch the surface now on the many visual, olfactory, auditory, instinctive and hormonal components that contribute to the way in which a dog perceives a person.

Although often forgotten from a human perspective, olfactory signals play a very significant role in canine interpretations. Dogs, like any species, will make decisions based on all of their senses if possible, but scents often take priority over other forms of information in canine brains. Anyone who has ever spent time with a dog will know how highly they value smells, especially the longer-muzzled breeds. Dogs not only gain information about each other through olfactory cues, their noses also equip them with incredible detective abilities. As scent-detecting dogs are able to find a missing person through indistinct trails of day-old scents, it would not be at all surprising if they also used their noses to shape their behaviour towards people they meet. Often a trigger of human embarrassment, it is well-known that dogs like to investigate unknown people by honing in on their genital area. Interestingly, this investigatory behaviour is less common when dogs greet familiar people, to whom they usually focus attention on the upper body, possibly reading more into behavioural and social signals [Filatre et al., 1991]. This is important to note, as it suggests that dogs may place more weight on scents, particularly the very gender-specific genital odours, when faced with a stranger and that this information may override any other signals that would be picked up by focussing attention on body language and actions. A previous study found that, even if behavioural and motion cues are controlled by asking both genders to perform identical behaviours, such as sitting perfectly still, dogs are still significantly more wary of the men [Lore & Eisenberg, 1986].

Regardless of their behaviour, posture, vocalisation and other consciously-controlled cues, humans unwittingly give away crucial details about their state, health, gender, environment, emotions and even genetics within their body odours [de Groot et al., 2017]. There are fundamental differences between the scents of male and female humans. Potency is the most obvious different, with men possessing much more active apocrine glands. These glands produce sweat rich in chemicals, particularly in response to fear states. Men also tend to have larger populations of naturally-ocurring bacteria present in these glands, exacerbating the smell [de Groot, 2015]. Therefore, men will smell much more potent through the nose of any receiver, especially a highly scent-sensitive dog and this scent is also harder for men to conceal. According to research, dogs appear to be significantly more attracted to the odours produced by women and also find it easier to distinguish between the odours of individual female humans, possibly due to the lower potency [Jezierski et al., 2012]. Dogs also react positively to the smell of familiar humans, the detection of which activates the reward centre in a dog’s brain, as opposed to unfamiliar controls [Berns et al., 2015]. Clearly, dogs can not only recognise the scent of familiar humans, they can also distinguish between and remember individual human scents, a skill which requires a significant degree of mastery, considering it crosses species barriers.

The chemicals produced by an individual’s body not only function to regulate their own physiology and behaviour, they can also have an effect on other members of the same species and, in some cases, other species too. Considering the superior sniffing ability of dogs and their co-evolution alongside humankind, they are well-equipped to detect certain chemicals emitted by a human’s body and can act upon this, whether consciously or otherwise. There is growing evidence to show how dogs and even humans are affected by cross-species chemical signalling. Except in forms of sexual signalling, states conveyed or transferred through scents tend to be negative, mostly related to anxiety, fear or aggression. Due to the ambiguity of social communication, and the ability of intelligent species to intentionally deceive others, it is evolutionarily advantageous for an individual to be able to detect potential threats through an unambiguous signal that is not under conscious control, such as body odour. Furthermore, as social animals are able to modify their behaviour independently of their internal state or transient emotions, it is also advantageous to survival if an individual’s brain will override this conflicting information in preference of basic olfactory cues. Thus, a dog is more likely to react upon chemical signals conveyed through scent when they are confronted with an unfamiliar or threatening situation or person than when they are in a familiar or relaxing environment [Mutic et al., 2016]. Chemical signals conveyed in scents are capable of causing emotional contagion, whereby an emotional change in one individual induces an unconscious and parallel emotional change in another. Consequently, if a person is feeling stressed, this could plausibly induce an analogous stress response in a proximal dog [de Groot et al., 2012]. Scents are important to consider when assessing canine fear of men for several reasons. Significantly, due to the stronger levels of testosterone, androstone and more potent sweat glands in men, the chemicals produced during stress or fear are much stronger in male humans than women. Furthermore, even in a relaxed state, a male human’s sweat and other bodily secretions will naturally contain higher concentrations of the chemicals that signify stress or fear [Sommerville & Broom, 2001]. In studies on humans, participants were reliably able to identify the smell of fear in male, but not female, sweat [de Groot, 2015]. If increased chemosignals in male odour can be detected by, relatively anosmic, humans, it is highly possible that canines, particularly anxious individuals, will show a heightened awareness to the scent information produced by men. In addition, testosterone, a hormone found in much higher concentrations in male humans, is a behavioural mediator and leads to increased aggression in the individual and others in his vicinity [Overall et al. 2001]. The fact that men possess stronger odours, release more signals of stress and have higher circulating testosterone than women, could significantly contribute to a dog’s greater wariness and reactivity towards men. This will be exacerbated when the dog is already feeling anxious and therefore more likely to evaluate an individual based on odour than other situational cues.

Recently, scientists have proven that chemosignals produced through scents can transfer across species barriers, particularly when the meaning behind the odour may entail negative consequences for the receiver. For example,, if humans are exposed to sweat rich in fear chemosignals, an emotional contagion response occurs, whereby the receiving humans display physiological signs of stress, despite no other cues being present [de Groot et al., 2012]. Female humans were most receptive to these cues and, when instructed to smell the testosterone and adrenaline-rich scent of fearful men, women possessed significantly increased cortisol levels than when sniffing a neutral control [Wyart et al., 2007]. This shows that the chemicals circulating in a human’s body during fearful states do not only affect that human’s behaviour, they also cause similar chemical re