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    dawn miller

    breeding for a particular color may not be the healthiest thing for our dogs. No surprise there. Have you folks been working on anything similar to this? The news typically doesn’t tell the entire story.


    kathleen morrill

    Hi Dawn,

    This article does a good job at explaining what’s at play: chocolate being recessive and smaller gene pools. The full paper can be found here, and explores more than just the relationship between color and health. It has a lot of good information for anyone interested with labradors or caring for labradors!

    The roots of this breeding isolation may go both ways: breeding specifically for chocolates, and breeding for *not* chocolate. Some non-chocolate breeders that want to avoid “Dudley” labradors (brown-nosed yellows) will make sure that the recessive chocolate allele is excluded from their gene pool.

    Anecdotally, I’ve heard people say “chocolate labs are crazy” (has anyone else heard this?)… with the information we collect in Darwin’s Dogs — behavioral surveys, color and breed (owner-reported), and genetic information — we might be able to test the veracity of that statement.



    One thing that puzzled me about this study…yellow is recessive too, and at least in the population studied, not that much more common than chocolate (27.8% yellow vs. 23.8% chocolate), so it’s not particularly obvious to me why they only report two median longevity figures–one for chocolates and one for “non-chocolates”–rather than breaking down blacks and yellows separately? They do suggest that “[t]he significantly shorter lifespan of chocolate dogs compared with non-chocolate dogs may reflect differences in lifetime burden of disease, notably disorders of the integument…that may create differences in accumulated immune response,” for which they cite as evidence that chocolates had the highest rates of one specific ear disease and one specific skin disease. Okay, but…why can’t you tell me first what the longevity difference between blacks and yellows is? lol. Maybe I’m missing something here?

    Anyway, while I know little about Labs personally, I do know a few people who are active in various sports with field-bred Labs (blacks and yellows), and am told by them that you “never” see chocolates among the high-ranking field or sport dogs, and only rarely in service work. I find it hard to believe that serious field, sport and service breeders (as opposed to show breeders) would avoid chocolates simply because they don’t want that “Dudley look,” IF there were lots of chocolates with great working potential available for them to use in their breeding programs. (Although maybe I’m being naive there!) So…I’m also wondering if perhaps chocolate (but not yellow) was originally a highly uncommon color in the breed, and only later became (relatively) popularized, through the show ring? or, perhaps was subject from a very early stage in the breed’s development to some (now-forgotten?) prejudice a bit more insidious than fear of the Dudley look??


    dawn miller

    I’m not too sure about labs. being more of a fan of German Shepherds. The white German Shepherd is seldom used for anything other than a family pet. They have a reputation for being a “soft temperament” dog. Perhaps it is the same concept as the “crazy” chocolate labs.


    lindsay gaudet


    The article that Kathleen linked to does list the longevity difference. Yellow and black labs lived, on average, 12.1 years (combined), compared with 10.7 years for chocolate labs – a difference of 1.4 years. Not huge, but statistically significant (i.e., unlikely to be due to chance alone).



    Hi Lindsay — I think(?) you meant to reply to me. My question was why they didn’t break down longevity for blacks and yellows separately, as opposed to averaging them together under “non-chocolate.” Especially since the implication is that chocolate being a recessive may have something to do with the longevity difference, when in fact yellow is a recessive too.

    It may be that there’s simply no statistically significant difference in longevity between blacks and yellows–that would perhaps fit with what I was speculating might be a breed history in which chocolates (but not yellows) were once quite uncommon, and only recently experienced a dramatic increase in numbers due to color-driven show/pet market breeding. I don’t know enough abut Lab breeding to know how common it is for breeders to concertedly select for yellow vs. freely breeding yellows and blacks together based on other criteria (working ability, conformation etc.) and just letting the chips fall where they may in terms of color.

    Still, as far as I can see, the study doesn’t actually say one way or another whether there was, in fact, any statistically significant longevity difference between blacks and yellows.

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