For the last 18 months, I have been collecting data on the lifespan of Standard Poodles, and the causes of death. Recently, we surpassed theobjective of 300 reports, and I would like to present a brief summary of the major results.
This survey, like most of its kind, is not a random survey. That would have involved selecting a random sample of registered poodles, locating their owners, and ensuring that all respond. Such a goal is very difficult to achieve. Any survey that depends on voluntary responses from a possibly-biased subset of the total has to be interpreted cautiously. Human mortality is far more readily assessed, as almost all deaths are reported, and statistics compiled by government agencies.
In total, there were 349 responses ranging from single individuals to several groups of 15 or more contributed by several breeders. Deaths that were clearly accidental were excluded . Not all the data could be used for all aspects of the analysis. For some, adequate pedigrees could not be established, thereby preventing the calculation of inbreeding coefficients. About 15 percent did not include the cause of death.
The dogs reported were 53% female. 71% were black and 74% were born between 1970 and 1990. Average inbreeding calculated from a 10-generation pedigree was 18.4%
When the percentage surviving is plotted against age in a human population, such as in the U.S. or Canada, the decline is very gradual up to around 55 yrs and then drops fairly rapidly. Survival drops to 50% at about 78 years and to 25% at 87 years. In contrast, wild animals even the large predators experience a sharp initial drop due to predation, disease and accident, a mid-life period of gradual decline, and a more rapid decline again in old age. However, a domestic dog, living with man, might be expected to survive early life better than a wolf, coyote or jackal pup, and therefore yield a survivorship curve similar to man.
In two breeds that have been studied, the St. Bernard and the Bearded Collie (see longevity1.html) survival drops off more rapidly from birth through mid-life than might be expected. In the St. Bernard, the decline is almost linear. The poodle data closely matches that for the Bearded Collie. However, if the poodle data is subdivided by inbreeding level, an interesting picture emerges. (Inbreeding coefficients were based on 10-generation pedigrees.)
Inbreeding 75% 50% 25% N 0-6.25% 12.8 14.3 15.0 39 6.25-12.5% 8.2 11.7 14.3 63 12.5-25% 7.5 10.8 13.0 141 over 25% 7.2 10.5 13.8 71
The difference between those inbred to less than 6.25%, the equivalent of a mating between first cousins sharing no other common ancestry, and those over 25%, is striking. Half of the latter die by 10.5 yrs while more than 3/4 of the low-bred dogs are still alive. The average lifespan differs by almost four years! Furthermore, if the data for the under 6.25% group is compared to human survival, multiplying by 5.5, the match is almost perfect.
This is not to say that low-inbred dogs are guaranteed a long life. Some still die of early-onset lethal genetic diseases such as JRD. Nor are they immune to cancer, which appears to play no favourites with respect to inbreeding. However, even those who die of cancer appear to live longer than the more highly inbred members of the population, perhaps because they are genetically more fit.
Neither does a high inbreeding coefficient guarantee early death. The oldest poodle reported, who reached a remarkable 21 years, was just over 26% inbred. Whether these long-lived, highly-inbred poodles are simply luckier than the others, or reflect careful selection to eliminate genetic problems from a line is not clear.
Note: The average 10-generation inbreeding of ~ 18% is not an unusually high level for purebred dogs.
Dr. John B. Armstrong
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