Active and social life is associated with lower non-social fearfulness in pet dogs

Demographics

We studied the environmental factors for fear of fireworks (n = 9,613), thunder (n = 9,513), novel situations (n = 6,945), and fear of heights and surfaces (n = 2,932). The fear of fireworks sample included 6,732 non-fearful and 2,881 fearful dogs with a mean age of 4.8 years (range 2 months to 18 years).

The fear or thunder sample included 7,809 non-fearful and 1,704 fearful dogs with a mean age of 4.7 years (range 2 months to 17 years). The fear of novel situations sample included 6,062 non-fearful and 883 fearful dogs with a mean age of 4.6 years (range 2 months to 18 years). The fear of surfaces and heights sample included 1,212 non-fearful and 1,720 fearful dogs with a mean age of 5.1 years (range 3 months to 16 years). In all sample sets, 52% of the dogs were females. More detailed descriptive statistics and lists of included breeds and the number of individuals per breed are presented in the Supplementary Table S1.

Factors associated with fear of fireworks

Logistic regression analysis identified several environmental and demographic factors associated with fear of fireworks, including age, socialisation score, neutering, activities/training, breed, owner’s dog experience, and dogs in the family (Table 1).

We found breed differences in the likelihood of fear of fireworks. The most fearful breeds were Cairn Terrier, mixed breed, and Pembroke Welsh Corgi: the least fearful breeds were Labrador Retriever, German Shepherd Dog, and Miniature Poodle (Fig. 1a). All pairwise breed differences are shown in Supplementary Table S8.

The probability of fear of fireworks increased with age until 10 years of age and decreased thereafter (χ² = 146.8, DF = 1, p < 0.0001, quadratic effect: χ² = 73.98, DF = 1, p < 0.0001) (Table 1, Fig. 1b). Dogs with less socialisation experiences had a higher probability of fear of fireworks (χ² = 26.15, DF = 1, p < 0.0001) (Table 1, Fig. 1c).

Dogs participating less frequently in activities and training were more fearful towards fireworks. More specifically, dogs participating in activities and training only seldom/never were more likely to be fearful than dogs that trained sometimes (odds ratio [OR] = 1.26, p = 0.0031) or at least weekly (OR = 1.41, p = 0.0004) (Supplementary Table S2, Fig. 1d). If the dog was the only dog in the family, it had a higher probability to show fear of fireworks than if the dog had dog company (OR = 1.44, p = 0.0004) (Supplementary Table S2, Fig. 1e).

There was no significant difference between female and male dogs (OR = 1.01, p = 0.8908) (Supplementary Table S2, Supplementary Fig. S1a). Neutered dogs were more likely to show fear of fireworks than intact dogs (OR = 0.75, p = 0.0004) (Supplementary Table S2, Supplementary Fig. S1b). If the dog was the owner’s first dog, it was more likely fearful than if the dog was not the first dog (OR = 1.53, p < 0.0001) (Supplementary Table S2, Supplementary Fig. S1c).

Factors associated with fear of thunder

Logistic regression analysis identified several environmental and demographic factors associated with fear of thunder, including age, socialisation score, neutering, activities/training, breed, dogs in the family, daily exercise, and body size (Table 1).

There were also differences between several breeds in the likelihood of fear of thunder. Lagotto Romagnolo, Cairn Terrier, and Rough Collie were the most fearful breeds whereas Miniature Poodle, Chinese Crested Dog, and Labrador Retriever were the least fearful breeds (Fig. 2a). All pairwise breed differences are shown in Supplementary Table S9.

The probability of fear of thunder increased with age until 10 years of age and decreased thereafter (χ² = 187.62, DF = 1, p < 0.0001, quadratic effect: χ² = 92.5, DF = 1, p < 0.0001) (Table 1, Fig. 2b). Dogs with less socialisation experiences were more likely fearful towards thunder (χ² = 21.79, DF = 1, p < 0.0001) (Table 1, Fig. 2c).

Dogs participating less frequently in activities and training were more fearful towards thunder. More specifically, dogs participating in activities and training only seldom/never or sometimes were more likely fearful than dogs that trained at least weekly (OR = 1.36, P = 0.0001; OR = 1.23, p = 0.0037, respectively) (Supplementary Table S3, Fig. 2d). If the dog was the only dog in the family, it had a higher probability to show fear of thunder than if the dog had dog company (OR = 1.45, p = 0.0006) (Supplementary Table S3, Fig. 2e).

Female and male dogs were equally fearful of thunder (OR = 0.96, p = 0.4863) (Supplementary Table S3, Supplementary Fig. 2a). Dogs that exercised 1–2 h or 2–3 h were less fearful toward thunder than dogs that exercised more than 3 h (OR = 0.83, P = 0.0412; OR = 0.78, p = 0.008, respectively) (Supplementary Table S3, Supplementary Fig. S2b). Neutered dogs were more likely to have fear of thunder than intact dogs (OR = 1.55, p = 0.0006) (Supplementary Table S3, Supplementary Fig. S2c). While large dogs were less likely to have fear of thunder than to small dogs (OR = 0.72, p = 0.0004), but there was no significant difference between small and medium dogs (OR = 0.82, p = 0.0981), or between medium and large dogs (OR = 0.88, p = 0.1669) (Supplementary Table S3, Supplementary Fig. S2d).

Factors associated with fear of novel situations

Logistic regression analysis identified several environmental and demographic factors associated with fear of novel situations, including age, socialisation, urban environment score, sterilisation, family size, activities/training, and the interaction of sex and sterilisation (Table 2).

The probability of fear of novel situations increased with age until 5 years of age and decreased thereafter (χ² = 7.52, DF = 1, p = 0.0061, quadratic effect: χ² = 12.6, DF = 1, p = 0.0004) (Table 2, Fig. 3a). Dogs with less socialisation experiences had higher probabilities of fear of novel situations (χ² = 157.18, DF = 1, p < 0.0001) (Table 2, Fig. 3b). Dogs with higher “urban environment score” were more fearful in novel situations (χ² = 12.31, DF = 1, p = 0.0010) (Table 2, Fig. 3c).

We found a significant interaction between sex and sterilisation. Intact males were less fearful in novel situations when compared to intact females (OR = 0.81, p = 0.0373). There was no difference between neutered males and females (OR = 1.23, p = 0.1292). Intact males were less fearful in novel situations than neutered males (OR = 0.494, p = 0.0003); and intact females were also less fearful when compared to neutered females (OR = 0.75, p = 0.0187) (Supplementary Table S4, Fig. 3d).

Dogs participating less frequently in activities and training were more fearful in novel situations. More specifically, dogs participating in activities and training only seldom/never were more likely fearful than dogs that trained sometimes (OR = 1.67, p = 0.0003) or at least weekly (OR = 1.84, p = 0.0003) (Supplementary Table S4, Fig. 3e).

A larger family size was associated with higher probabilities of fear of novel situations. Dogs living with one adult (“single”) were less likely to have fear of novel situations than dogs living in families with two children (OR = 0.66, p = 0.0048) or in a larger family (OR = 0.57, p = 0.0003). Dogs living with couples were less likely fearful than dogs living with a larger family (OR = 0.70, p = 0.0025) (Supplementary Table S4, Supplementary Fig. S3a).

Factors associated with fear of surfaces and heights

Logistic regression analysis identified several environmental and demographic factors associated with fear of surfaces and heights, including age, socialisation, urban environment, sex, activities/training, breed, owner’s dog experience, dogs in the family, daily exercise, body size, and fearfulness (Table 2).

We found several breed differences in the likelihood of fear of surfaces and heights. Rough Collie, Cairn Terrier, and Chihuahua had the highest probabilities of fear of surfaces and heights whereas Coton de Tuléar, Border Collie, and Lagotto Romagnolo had the lowest probabilities of fear of surfaces and heights (Fig. 4a). All pairwise breed differences are shown in Supplementary Table S10.

Dogs living in a more urban environment had a higher probability of fear of surfaces and heights (χ² = 7.27, DF = 1, p = 0.0007) (Table 2, Fig. 4b). Large and medium dogs were less likely to show fear of surfaces and heights than small dogs (OR = 0.40, p < 0.0001; OR = 0.369, p = 0.0021, respectively) (Supplementary Table S5, Fig. 4c). Only dogs in the families were more fearful than dogs living with other dogs (OR = 1.88, p = 0.0021) (Supplementary Table S5, Fig. 4d).

Dogs participating less frequently in activities and training were more likely to show fear of surfaces and heights. More specifically, dogs participating in activities and training only seldom/never were more likely fearful than dogs training sometimes (OR = 2.06, p = 0.0021) or at least weekly (OR = 2.26, p = 0.0021) (Supplementary Table S5, Fig. 4e).

Higher fearfulness was associated with higher probabilities of also having fear of surfaces and heights, as dogs showing no fear were less likely to have fear of surfaces and heights than dogs showing moderate (OR = 0.61, p < 0.0001) or high (OR = 0.36, p < 0.0001) levels of fear. Dogs with moderate fearfulness were also less likely to have a fear of surfaces and heights than dogs with high fearfulness (OR = 0.59, p < 0.0001) (Supplementary Table S5, Fig. 4f).

Age was not associated with fear of surfaces and heights (linear effect: χ² = 1.75, DF = 1, p = 0.186; quadratic effect: χ² = 3.38, DF = 1, p = 0.066) (Table 2, Supplementary Fig. S4a). Socialisation score (χ² = 0.07, DF = 1, p = 0.712; quadratic effect: χ² = 1.28, DF = 1, p = 0.257) (Table 2, Supplementary Fig. S4b) and daily exercise (χ² = 10.90, DF = 3, p = 0.076) (Supplementary Table S5, Supplementary Fig. S4e) were also not associated. If the dog was the owner’s first dog, it was more likely to show fear of surfaces and heights than if the dog was not the first dog (OR = 1.49, p = 0.0021) (Supplementary Table S5, Supplementary Fig. S4c). There was also no significant difference between the female and male dogs (OR = 1.01, p = 0.911) (Supplementary Table S5, Supplementary Fig. S4d).

A summary of demographic and environmental factors associated with non-social fear in dogs are shown in Fig. 5.

Source: Ecology - nature.com