There is a new study that was just published in the August issue of Veterinary Record.
The Italian study compared the owner-reported behaviors of 70 dogs that were separated from their litters at 30-40 days with the owner-reported behaviors of 70 dogs that were separated from their liters at 2 months, and studied whether behavioral issues arose from dogs being separated from their litters at the younger age.
Based on the study's results, here are the percentage of dogs in the study that developed the specific behavioral problem for each group - the first number respresents those dogs that were separated from their owners early, the second number those that were separated later.
Excessive Barking: 63/21
Fearfulness on walks: 53/7
Reactivity to noises: 81/39
Toy possessiveness: 34/4
Food possessiveness: 34/7
Aversion to strangers: 60/24
Stranger aggression: 23/4
Owner aggression: 17/9
Play biting: 28/3
Tail chasing: 14/1
House Soiling: 26/10
Specific definitions of each of these is included in the study.
There is a further analysis in the study -- a large part of which shows that dogs that are bought from pet stores have significantly greater issues than dogs that were obtained from other sources.
From the discussion:
"The results of the present study indicate that early separation of a puppy from the litter is an experience that may increase the animal's chances of showing potentially problematic behaviors as an adult. Moreover, the effect can be further potentiated by the puppy's first environment"
There are certainly a few other factors that could have influenced the study. First off, there were only 70 dogs in each group - -so a pretty small sample size. Secondly, there was a significant difference in breeds of dogs involved (67% of the dogs that were not separated from their litters until 2 months were purebred dogs while 100% of the dogs in the early separation group were mixed-breed dogs). The study didn't not attempt to take into account owner-behavior either.
However, the study is still worth examining -- in large part because nothing in the study is consistent with what you would hear from most professional breeders, behaviorists, and previous studies on the topic.
The study does show a very strong correlation (likely causal) between aggressive-types behaviors like stranger aggression, owner aggression, and possession aggression and dogs being removed from their litters at 30-40 days. The study also suggests that there are several fearfulness behaviors (fearfulness on walks, possession aggression, aversion to strangers) that may result from a lack of confidence that would be garnered by extending the time with their litters. The differences in all of these behaviors is very significant between the early separation group and the not-early separation group.
This shouldn't be a surprise to most people -- but does highlight that there could be some other significant issues that lead to aggressive behavior that doesn't show up on anyone's dog bite 'statistics'. In addition to increased aggressive behavior, it is also worth noting that removal from a litter too early (in this case before 16 weeks) has also been shown to decrease bite inhibition -- which is a major determinent between a dog that issues a "bite" and a full on "attack".
It is also likely very telling that dogs that were removed from litters early had a better chance of good behavior if the dog was not immediately put into a non-home environment in a pet shop. It seems clear that removing the dog from a its litter, where it would receive natural socialization, to another situation where it would receive less socialization enhances the problems (the study calls this an epigenetic impact -- which we've also discussed on this blog). This would logically suggest that the same impact would be had on dogs removed from their litters and put on chains full time.
According to the study:
"In consclusion, early separation from the dam and littermates, especially when combined with housing in a pet shop, might affect the capacity of a puppy to adapt to new environmental conditions and social relationships later in life."
If we are going to have serious conversations about canine aggression, it is imperative that we drop the discussion of "breeds" being the problem, and start listening to science and experts. Science has repeated told us that breed is not a significant differentiator in aggressive behavior, and that environmental factors, such as early removal from litters and early upbringing have a much more dramatic impact.
If we were to focus on these environmental factors, which is substantiated by science as being a factor, instead of focsusing on 'breed' (which visual identification studies have shown us is unreliable), we would have a much greater impact on solving the dog bite issues in this country. The time to start is yesterday.
You can read the study in its entirety here (it's only 6 pages, so not long).