Are pets our symbiotes? It’s a mutually beneficial relationship between at least two different species.
It sure looks like that for many pets and domesticated animals. How many dogs are there in the world compared to wolves?
In the broadest sense, symbiosis can refer to close relationships that are not mutually beneficial, such as parasitism. Nowadays, however, the term is often used as being synonymous with mutualism, in which both species benefit.
The relationship between humans and their pets and other domestic animals is certainly symbiotic in the broad sense; it is usually mutualistic as well. (In biological terms this is true even for domestic animals used for food. Although an individual calf used for veal doesn’t benefit, cattle as a species definitely do.)
The OED disagrees, and has:
It looks from that as if the non-parasitic definition preceded the inclusion of the parasitic.
The OED does not disagree with what I wrote. The first usage cited includes “commensalism,” in which one party benefits while the other is not affected, reflecting the original broader sense of the term. In any case, a few citations from the OED cannot really be used to trace the history of the scientific use of the term.
I’ve often heard that people who have pets, especially dogs, live longer. I can see where to logic comes from ( daily excercise for both owner and dog), but wonder how this kind of data could actually be collected and processed.
As a dog owner I like the idea, but I’m not certain I’m any healthier now, than before getting the doggie.
This page contains varous definitions of symbiosis; the basic concept is that at least one (not necessarily both) associates benefit. There is also an extended discussion of the symbiotic relationships of humans and their domesticates.
Not just exercise; stress relief. Animal companionship comforts most people.
The more likely cause is that people who have enough money to support a pet also have enough money to have better living conditions, food, health care, etc. And there have been many studies to show that those are clearly related to life expectancy.
I haven’t heard of studies that clearly show a causal relationship between pet ownership to life expectancy. (‘Surveys’ sponsored by pet food sellers don’t count.)