Posts Tagged With: aggression

Day 9: Are Small Breed Dogs Genetically Predisposed To Fearfulness?

This weekend is dedicated to watching the SPARCS conference. Of course not everything is interesting to me, but I try to listen to as many presentations as I can because sometimes you find hidden gems in most unlikely places. Like James Serpell’s presentation on C-BARQ.

C-BARQ is an online questionnaire that was developed as a tool of measuring dog behavior problems. You can go over to, answer a bunch of questions about your dog and get a score on his fear/aggressiveness/etc. It will also show you how these scores compare to other dogs of same breed and your data will be entered in their database. They say it currently contains data for more than 25,000 pet dogs and 22,000 guide/service dogs. So… a lot.

Now this is all interesting, but I have filled Ruby’s C-BARQ questionnaire two years ago so this was old news to me. James started with explanation about how it was developed and why they think it’s valid and reliable (yawn), so I went to the kitchen to bake some muffins instead. Then something attracted my attention. You see, with such huge numbers of participants you can get some interesting information about how breeds of dogs differ. He only showed the 30 most popular breeds in USA so unfortunately there is no information on whippets, but the statistics are fascinating nevertheless.

Keeping in mind that he only showed the 30 most popular breeds in USA, the breeds most likely to exhibit stranger-directed fear were: Chihuahua, Dachshund, Dachshund (Miniature), Maltese, Poodle (Toy, but not Miniature or Standard), Shetland Sheepdog, Yorkshire Terrier

The breeds least likely to exhibit stranger-related fear: Golden Retriever, Rottweiler, Siberian Husky

The breeds most likely to exhibit dog-directed fear were almost the same as for stranger-directed fear: Beagle, Chihuahua, Dachshund, Dachshund (Miniature), Maltese, Poodle (Toy, a bit less Miniature, but not Standard), Shih Tzu, Yorkshire Terrier


Did you notice that all these breeds are small? Look at the graph above, there are plenty of big breeds up there… But obviously not all small breeds tend to be fearful, some stay well below that red line.

For nonsocial fear: Beagle, Chihuahua, Dachshund, Dachshund (Miniature), Maltese, Pembroke Welsh Corgi, Poodle (Toy), Sheltie Sheepdog, Shih Tzu, Yorkshire Terrier

For stranger-direction aggression: Chihuahua, Dachshund, Dachshund (Miniature), Maltese, Miniature Schnauzer, Poodle (Toy)

The statistics also show that stranger-direction aggression and stranger-related fear are correlated, which isn’t too surprising since fear can be a powerful motivator behind aggression.

The relationship between body size and fear looked very interesting as well, though it is clearly not a straightforward one. The lighter the dog, the more fearful they tend to be:


(Mostly) same breeds and (mostly) small also scored higher than average on owner-directed aggression and attachment/attention seeking. Serpell states several possible reasons for this, some of which are related to how owners treat small dogs. But interestingly King Charles Spaniel and the Havanese don’t show these anxiety-related traits despite their size, so he postulates that these behavioral differences could reflect genetic/physiological correlates of selection for small body size.

Interestingly there are some studies actually showing that miniature poodles have significantly lower serum levels of Insulin-like Growth Factor-1 (IGF1) (Eigenmann et al., 1984; Guler et al., 1989). In another study German shorthaired pointers were selected deliberately for nervousness/fearfulness and the more fearful they were the lower their IGF1 levels were (Uhde et al, 1992). Molecular geneticists have even found gene pairs associated with the IGF1 gene that are present in toy or miniature dog breeds, but are absent in wolves and very rare among large dog breeds (Sutter et al., 2007; Grey et al., 2010). He says that this doesn’t prove that low IGF1 levels cause those behaviors, but some connection is there.

I think we wrongly assume that we can select for dog’s outward appearance when breeding and the behavior will remain the same. The Poodle tells a clear story: Standard poodle being less fearful and aggressive then his Mini and Toy counterparts. This is the same breed! And it doesn’t end with selecting for size, either. The English Cocker Spaniel Rage Syndrome has been found to vary greatly by the coat color, with solid colored dogs being more affected than parti-colored. The English Springer Spaniel also suffers from Rage Syndrome. Wikipedia says “In English Springer Spaniels, the appearance of rage syndrome has been traced back to a winner at the Westminster Kennel Club show who went on to become a top stud.” (see

You probably know where this is going. We cannot afford to breed dogs solely on the quality of their looks. There is so much more that goes into a good companion – physical health, mental health, ability to do the task it was originally created to do. I hope the world wakes up before it’s too late.

Categories: Uncategorized | Tags: , , , | 2 Comments

Blog at

%d bloggers like this: