Really appreciate all the answers. I guess this one summarizes it for me:
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It’s more difficult to breed for extended life span because whether or not an animal will have a long birth isn’t evident at birth. You only know it’s long-lived after the fact. And old animals will often be less fertile than young ones.
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I acknowledge that the life expectancy for dogs and cats has been going up, similarly to humans and probably for similar reasons (i.e. access to better health care, better diet, etc). What I was looking for is life span increases. I guess it’s more difficult than I thought it was even for animals…I guess I had this idea in my head that the main stumbling block to doing this for humans was more ethical or squimishness (or religious reasons) with monkeying with Human genes and doing human experimentation, since we’ve been able to extend mice and rat life spans for a while now. But it seems more complicated and difficult than I guess I envisioned.
Again, thanks for the replies all…I just wanted to check in to say I appreciated them and hadn’t forgotten about the thread, but I really have very little knowledge on this stuff and just wanted to see what folks here thought.
A lot of the mouse/rat research uses caloric restriction to extend their lives.
Whether or not caloric restriction would even work in humans, cats, and dogs, it’s just really HARD to do. Look how much trouble we have controlling obesity, when we know it is harmful to health.
I think there are few loving pet owners who could long keep their pets in a continually starved condition. I also think many of these pets would be far less lovable in that condition.
Anecdotally, we just raised a puppy for a service organization. She came out a tad overweight, so not starved. Not that you could tell that by how she acted. Every bit of food (and non-food) went right in her mouth. Imagine what she would be like if she was truly constantly starved.
Zombie pets and all that. But I saw this article on CNN and thought I’d post it here.
Yeah, this is totally experimental, and a couple of examples where it seems to help don’t constitute something that really works. However, it sounds like it MIGHT be something. It would be great if our pets could live longer and healthier lives. I think at 13 it might be worth the risk to try this out if you could get your pet in the program.
There’s the billion heartbeat principle. The basic rule if that mammals have a lifespan equal to the amount of time it takes for their heart to beat a billion times. It doesn’t matter if it’s a mouse or a dog or a bear or an elephant or a whale - they all have a lifespan equal to around a billion heartbeats. Some mammals have quick heart rates and short life spans and other mammals have slower heart rates and longer life spans. But they all follow the billion heartbeat rule.
With one exceptions: primates. Chimpanzees, gorillas and orangutans all live significantly longer than a billion heartbeats. And humans live even longer than other primates. The average human life span is over two billion heartbeats long. If we followed the normal rule, we would die sometime around the age of thirty.
There’s another exception: some birds. For example, hummingbirds’ hearts beat at an incredibly fast rate (up to 1,260 beats per minute), yet they can live as long as 10 - 12 years.
Add bats to that list too. Some species at least (eg: little brown bat) are about the size of small rodents and might average several hundred BPM, but often live for decades. A mouse or hamster the same size will only last 2-3 years.
We do, just by protecting them from the hazards of the wild. The longevity of the fox is listed as 5 years, coyotes and wolves “up to” ten or twelve in the wild, with the average orf median well below that outlier. So if wild canines have a natural life expectancy of 5-7 years, and dogs 10 to 15, domestic canines do live at least twice as long as their wild cousins.
In order to breed for longevity, you would need to know how old something will live to. In order to know how old something will live to, you have to wait for it to die. Dead things don’t breed.
That said, we now have a few tests that give a good prediction (for humans) on how long they are likely to live (telomeres length, methylation frequency, etc.) These techniques should work on most animals. So we would be able to tell how long-lived each member of a breeding pool is likely to live and cull (or prevent from breeding) the lower 50%. Over time, this should produce longer-lived animals.
Though it’s possible that this alone would be insufficient. If the biomarkers are testing for certain chemicals, then maybe increasing those chemicals in the body will be beneficial at a certain level but increasing it even more past that could start harming the animal and shortening its life, rather than extending it. So you might see one or two generations of improvement and then a decrease after that.
Ultimately, we would need to understand aging better. At the moment, we’re still not sure how it works.
No longer true, due to artificial insemination and frozen semen.
I have a friend who still offers breedings to her champion stallion, who actually died several years ago. But she has straws of frozen semen from him available for sale, and every year or so he has new offspring born.
Or you could do what Heinlein suggests in the Lazurus Long books. Pick out dogs and cats whose grand parents lived the longest and breed those together for 30 generations or so.
Pets have been bred for desirable qualities for millennia. And, that isn’t good enough for you? Are you sure you want to be married to your pet for 40 years? They have pets like that.
I have parrots. Of the current patch, 2 can have life expectancies in the mid-20’s and one into the mid-30’s, even 40. So some of us do that already. Parrots are some of those birds with high metabolisms and long lives.
Some parrots have life expectancies in the 50-75 year range, comparable with human beings.