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How Long Will Your Molosser Live?

A British study finds that size and head proportions are correlated with longevity in dogs

The bigger they are, the harder they fall.

That’s the message from a British study of canine longevity published this week.

Analyzing the data of more than 580,000 dogs provided by rescue groups, breed registries, pet-insurance companies, veterinary groups and others, the researchers focused on a number of possible factors contributing to early death, including breed, body size, sex and cephalic index (the ratio between the width and length of skull). Sorting the longevity estimates based on genetic relationships between the 150 breeds in the study, researchers drew the conclusion that “canine evolutionary history” — that is, how dogs were domesticated and then shaped into various breeds — is connected with breed lifespan. 


Survival curves for eight purebreds: Border Collie (dark blue, 13.1), Border Terrier (light blue, 14.2), Bulldog (green, 9.8), French Bulldog (red, 9.8), Labrador Retriever (orange, 13.1), Mastiff (purple, 9.0), Miniature Dachshund (pink, 12.2) and Pug (brown, 11.6). Crossbred are denoted light purple (12.0).


Among the study’s findings:

Purebred dogs live longer than crossbreds. Averaging together all the dogs, regardless of pedigree (or lack thereof), median survival was estimated at 12.5 years. However, purebreds turned out to be longer lived, with a median age of 12.7 years, compared to 12.0 for mixed breeds.

Female dogs live longer than males. Apparently, “female survival advantage” is a thing with mammals, and bitches are no exception: The study found that median survival for female dogs both purebred and mixed was 12.7 years, while for males it was 12.4 years.

Bigger breeds live longer than smaller ones. This, of course, is where Molosser lovers prick up their ears.

In mammals in general, a bigger body means you live longer, the study explains: Think about a fox compared to a mouse. But within the limits of a given species, the smaller the individual, the greater the likelihood of longer lifespan.

The study found that in large-breed dogs, both males and females had lower survival estimates (11.8) compared to small (12.7) and medium breeds (12.3).

Not surprisingly, given the study’s focus on size (and head proportions, which we’ll get to next), a number of Molosser breeds in the study had the lowest median mortality, including the Presa Canario (7.7), Cane Corso (8.1), Mastiff (9.0), St Bernard (9.3) and Neapolitan Mastiff (9.3).


Young Caucasian Shepherd Dog.


Perhaps the biggest shocker was the Caucasian Shepherd Dog, which scored the absolute lowest in life expectancy, at 5.4 years.

Other breeds most at risk from early death included the Bloodhound (9.3), Affenpinscher (9.3), Bulldog (9.8) and French Bulldog (9.8).

Breeds at risk least from early death included the Lancashire Heeler (15.4), Tibetan Spaniel (15.2), Shiba Inu (14.6), Papillon (14.5), Lakeland Terrier (14.2), Schipperke (14.2), Border Terrier (14.2), Italian Greyhound (14.0) and Miniature Dachshund (14.0).



Circular phylogeny representing ancestor‐to‐descendant breed relationship, along with median lifespan. Median lifespan for 148 purebreds. Hotter colors represent lower median lifespans.


Long-nosed dogs live longer that flatter-faced breeds. The study looked at breeds that were mesocephalic (with an average length of muzzle), 12.8 years); brachycephalic (shorter muzzle length — which includes Molosser breeds), 11.2 years, and dolichocephalic (longer muzzle length, such as Sighthound breeds), 12.1 years — concluding that “an interaction was evident between cephalic index and size.” It noted, however, that the biggest differences in longevity between the three head types were most apparent with medium-sized dogs.


Molossers in Focus


OK, so bigger isn’t better: That point the paper makes clear. But what’s interesting that all big dogs aren’t equal: There were some head-scratching discrepancies between them.



For example, compare the Neapolitan Mastiff, which the study says has a life expectancy of 9.3, to the Presa Canario, whose longevity drops precipitously to 7.7. Now, does that make any sense? The Mastino is a borderline giant breed with a lot of weight and wrinkle to carry on a not-always-supportive frame. And it outlives the more moderately built, lighter-bodied Presa Canario by almost a year and a half?

Maybe there is a reason other than genetic disease for the Presa’s surprisingly low life expectancy. For example, how many of the deaths reported to the study were for a non-health-related reason, such as temperament?

Both Neos and Presas are rare breeds in the United Kingdom, with Presas not even recognized by the Royal Kennel Club. (Thanks to a nod from King Charles last year, Britain’s kennel club is now permitted to use the word “Royal” as part of its official name.) As a result, related findings in this study — both positive and negative — could have more to do with the particular genetic make-up of a specific family or line than the breed as a whole.

On the flip side, how to explain the (relatively) extraordinary median lifespan of the Dogue de Bordeaux, at 11.1 years? It wasn’t long ago that we were publishing stories about how Dogues de Bordeaux were developing lymphoma before they hit five years old. Or the whopping median lifespan of 13.3 years for the Tibetan Mastiff? Even given the wide range within the breed when it comes to phenotype (Do Khyi versus Zang Ao, anyone?), that’s still quite a high number. In fact, it is identical to the median life expectancy for the longest-lived group in the study: small dogs with long noses.

“There’s something else going on there” aside from size and head type, one of the study’s co-authors, scientist Kirsten McMillan of Dogs Trust, which contributed data to the study, told Science News


Median lifespans of the lowest quartile of breeds plotted onto the breed phylogeny. Clusters with lower median lifespans are localized within three clades, or related groups with a common ancestor: the first including breeds such as the Caucasian Shepherd Dog, the second containing the Mastiffs and Bulldogs, and the third including the Presa Canario, Neapolitan Mastiff and Cane Corso.


In the end, perhaps the only conclusion one can definitely draw from this retrospective paper is that more study is needed. As the paper’s authors state in multiple places — almost an ongoing apologia — theirs is a limited study that has arrived at conclusions that other research has disputed. (That includes, but is not limited to, their findings on purebreds living longer than mixes and females living longer than males.) They stress that their conclusions cannot be generalized beyond British dogdom, and that a number of important variables were not addressed, including reproductive status (no differentiation between altered and unaltered animals) and cause of death. Significantly, the study — a little fewer than half of whose subjects were already deceased — contained no live dogs, nor was it able to isolate results from so-called “designer dogs,” which result from the crossing of two purebreds.

A lot of holes, to say the least.


Let’s Hear It for the Neos


Turning from head-scratching to back-patting, let’s conclude by lingering lovingly on that 9.3 number for Neapolitan Mastiff longevity. That is almost — not quite, but almost — double the life expectancy of the breed during its golden era in the 1990s, before hypertype turned too many dogs into melted cartoon gargoyles, when Caligola di Ponzano was winning Best in Show at nothing less than the World Dog Show, and when the amount of quality being produced in the breed was unrivaled.


Neapolitan Mastiff Caligola di Ponzano on a television appearance at more than seven years old.


Speaking of Caligola, his owner comments on the breed’s then-dismal lifespan in a charming clip of a typically ‘90s Italian talk show, with its busty showgirls and “Rocky” theme heralding the canine champion’s arrival: “That’s a record in itself,” says Antonio Pegoli when asked about Caligola’s age of seven and a half. “For a Mastino of great size … five years, six years, and they go.”

So, Mastino fanciers, give yourselves a well-deserved pat on the back. And, Caucasian Shepherd Dog lovers (in the U.K., at least): Time to start asking more questions!




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