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A week ago I was bitten in my face by a dog that originally came from an asylum. That dog is half Rottweiler. Some people claim that the history of the dog is probably different from what the asylum thinks or says, whereas other people claim that Rottweilers or male Rottweilers are unreliable. But let's not focus on this single occurrence and ask the wider question:

Is there scientific evidence to indicate that there are certain breeds that produce significant numbers of dogs that are inherently and unreliably aggressive, or is such aggression usually the consequence of how their owners raised them?

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  • $\begingroup$ How are dogs political? Anyway, we don't do political discussions here — they get vacuumed up very quickly. $\endgroup$ – David Oct 6 '19 at 21:44
  • $\begingroup$ @David An answer to the question would be an argument in the political debate whether certain dog breeds should be banned, as was once the case in Belgium. $\endgroup$ – Albert Hendriks Oct 7 '19 at 8:55
  • $\begingroup$ I see. But, as I said, this SE is only for objective biology questions and objective answers. In general I would advise not anticipating trouble with your post — it is more likely to provoke it than otherwise. Trust in the good sense of members until they prove otherwise, and then flag any inappropriate responses to the moderators. $\endgroup$ – David Oct 7 '19 at 9:42
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It seems that there are some important differences in dog aggression depending on the dog breed (towards strangers, owners, and other dogs):

enter image description here

That being said, it seems that a significant proportion of a dog's behavior can be due to its environment (training, etc), according to a study, this 'nurture' component might explain up to 80% in the variation in aggression (which should be considered when interpreting the other study I cite).

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  • $\begingroup$ For discriminating viewers: the error bars indicate a 95% confidence interval, i.e. the range of values for which we can be 95% certain to contain the true mean of the population. Notice the error bars are quite wide. Notice also the scale bars; we are always talking about < 1% of dogs (1-3 out of 138 dogs on average) so I would be wary of these pretty tiny differences. We're talking about being hit by lightning vs. winning the lottery statistics here. Interpret them with a grain of salt! $\endgroup$ – S Pr Oct 7 '19 at 11:38
  • $\begingroup$ For even more discriminating viewers: Notice the Y-scale represents a value that can vary in the [0,4] interval, which is the interval used in this particular technique (0-no aggression, 4-most aggression). So, these are not 'pretty tiny differences'. Basic statistics are easy to be misinterpreted. More info: sci-hub.tw/10.2460/javma.2003.223.1293 $\endgroup$ – TumbiSapichu Oct 7 '19 at 17:00
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    $\begingroup$ There are also very few other studies that replicate any dog breed findings. I would be as cautious as the authors themselves, who in their own words state that "the substantial within-breed variation in C-BARQ scores observed in this study suggests that it is inappropriate to make predictions about a given dog’s propensity for aggressive behavior based solely on its breed." And remember that the data is based on subjective questionnaire reporting online, which is difficult to gauge as trustworthy or true to reality, especially since we are talking about pets! $\endgroup$ – S Pr Oct 8 '19 at 10:30
  • $\begingroup$ You're on your right to be cautious, but 259 other papers citing this study are not "very few": bit.ly/31WZtDH - in any scientific field (biology specially) that is quite a significant number of citations. I quote another study citing the paper: "questionnaire surveys provide more detailed information about the dog's behaviour than behavioural tests, especially about low-frequency behaviours (Duffy et al., 2008)". (bit.ly/2MmDqzO). I'm sure the study is not perfect, but criticizing its statistics/design without knowledge of the matter is not very scientific either. $\endgroup$ – TumbiSapichu Oct 8 '19 at 19:34
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There is another study, in addition to that cited by @TumbiSapichu, that establishes a genetic component in canine aggression. This is: Zapata et al. (2016) BMC Genomics 17:572 and is entitled Genetic mapping of canine fear and aggression.

The study did not set out to establish which breeds, if any, are most aggressive, but started from the proposition that there might be a genetic component in canine aggression, and tested this by a genome-wide association (GWA) study on one cohort of different breeds. This established certain candidate genes, which were tested — and confirmed — on a second cohort. The authors of the paper conclude:

“We have mapped many canine fear and aggression traits to single haplotypes at the GNAT3-CD36 and IGSF1 loci. CD36 is widely expressed, but areas of the amygdala and hypothalamus are among the brain regions with highest enrichment; and CD36-knockout mice are known to have significantly increased anxiety and aggression. Both of the other genes have very high tissue-specificity and are very abundantly expressed in brain regions that comprise the core anatomy of fear and aggression – the amygdala to hypothalamic-pituitary-adrenal (HPA) axis. We propose that reduced-fear variants at these loci may have been involved in the domestication process.”

I appreciate that the reader may wish to see a graphic showing that Rottweilers are more aggressive than Yorkies, for example. However the paper clearly answers in the positive the question of whether there is a genetic component in canine aggression, and the paper has 20 pages and eight figures for anyone who wishes to tease out information regarding specific breeds. (I do not own a dog, so lack the incentive to do so myself.)

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