What do you think?

[seaglass]

My 10 yr old jack russell has arthritis in her back legs, it's managed with pain killers, and generally she's fine, but needs regular vet appointments to keep a check on her.

Last week, I saw a different vet in the practice, and he started telling me what a bad design four legged animals are, and that they're all prone to arthritis due to the bad positioning of their back legs.

So looking at most animals, only humans have straight legs (I'm probably wrong on this, but can't think of any at the moment) even chickens, on their two legs, have the same bentness (?!) as dogs legs. Most animals I can think of have 4 legs, and the back legs are similarly shaped.

So evolution has formed most animals to have problems with their back legs?

I sort of think that he was just filling in a silent moment with his inane theories, but wondered whether I am completely wrong about this - after all, he is the vet and knows far more about animals than I do, but this does seem a strange theory.

Sorry for the long and pointless post, this has kept me awake most of the weekend

What do you all think?

Well.... he could have a point ish....

Because of our intervention with animals by domesticating them and providing vet care etc, they live much longer than they were originally intended to by nature and, therefore, body structures are tested out to far larger extremes than they were designed for. This means that things like arthritis that would not show in a younger animal do start to show through. It is possible that four legs is a bad design for a longer lived animal but that nature never met that problem simply because the bones and joints were not needed to survive for that long...

But that is just my crackpot theory based on his crackpot theory

Formed to have problems in their old age. From an evolutionary standpoint, If the dog is healthy and vigorous during its most important reproductive years, than it doesn't matter what happens in their old age, especially if the same adaptation (4 legs) also gives them any advantages during youth and reproductive years.

So I think what the vet said is plausible.
Also human leg joints are quite different (seemingly opposite) from back legs in 4 legged mammals.
All joints wear out, we have this silly modern notion that aging isn't supposed to happen.

Balderdash.

4 legs better than 2 - much more stable over uneven ground, fewer back problems etc.

Arthritis occurs as a result of animals living longer (as the esteemed DMNC says) and genetic manipulation by humans. And too much exercise when young.

Your vet has been dipping into the ketamine, methinks

Lolololol @ esteemed

tis true.

Anyway, how exactly does this vet explain away knee and hip replacements in humans?

I didn't ask him about humans - my brain doesn't work quick enough to think of clever comments or questions straight away! It's taken me all weekend to sort out the jumble in my head and write the above post

Thankyou - more points to ponder and keep me awake tonight!

No idea where your vet got this theory really but certainly wasn't something we were taught at veterinary school! I agree with above posters that most arthritic change in our dogs is due to a mixture of breeding and how long they live for. In the natural world an older animal would only survive while it was agile on its legs - after that it would starve and/or become prey to other animals. Only the healthiest survive in the first place for long enough to breed so natural selection means that those with genetic advantage (ie good legs for canine/feline hunters) are more likely to have offspring and in turn they are more likely to survive and be healthy. In contrast our domestic dogs are all shapes and sizes - bowed legs, stunted legs, legs with knees that are too straight for the mechanics to work effectively etc. In a wild situation most of these individuals would just starve and not have a chance to breed - they would not be agile enough to hunt. In our homes we feed them, care for them and they have a good life span, but it is very common for them to develop arthritic changes even quite early in life. Sadly they cant tell us things start to hurt and it is only usually at a certain point that owners/vets become aware of the pain and start to medicate - usually when they are getting older. If many dogs were studied carefully in middle age there would already be arthritic changes visible though. It is certainly not unusual to see this on x-rays when something else is being looked for.

An aside - dogs/cats and chickens alike all have joints that bend the same way as each other - they are just different lengths between the joints and different parts of the "foot" that are walked on. Humans walk on a lot more of the lower limb as a foot than a dog does for example.

Thankyou for that
Good to have it from a vets perspective - I'll definately sleep easy tonight