Age - a question for my all-knowing friends-list

[andrewducker]

Ed was asking on Facebook what it would be like if we didn't age visibly so much - after all, other animals don't tend to.

Is this actually true?  Thinking about it, most other animals don't seem to get wrinkled in the same way, nor does their fur turn completely white or all fall out.  But is this just some animals?  Do other animals age visibly the same way we do?  Or is there something odd about people?

Comments

[andrewducker]

Are you sure your not just taking the fact that human hair goes grey as a measure because of human chauvanism?

I'm taking it as an obvious _visible_ change. Dogs do go a bit greyer around the face, and I can spot old dogs from young ones, but the changes do not seem as obvious as large chunks of hair not being there any more, or complete colour changes.

A probably arbitary decision would have to be made as to how long an animals life relates to a humans.
And if you used this factor then animals wouldn't live "relatively" shorter - because your factor would be the same in both cases, surely?

[endless-psych.livejournal.com]

Depends on differences between domestic and wild type life spans. You could perhaps work out how domestication has increased/decreased life span for certain animals by comparing wolf/dog cow/buffalo (or similar) etc. Then perhaps coming up with a rough approximation for some sort of way to measure ages relatively. But like I say arbitary.

?I'm taking it as an obvious _visible_ change.

Yes, obvious to humans. It's a no-brainer that we'd notice ourselfs ageing more then other species. As it's perhaps an indicator of fittness. What would be interesting would be to explore whether or not animals can detect age in members of their species. As this could indicate either way whether there are "obvious visible changes" or obvious changes involving other senses that make age salient for animals but not for humans.

Otherwise we are just talking about the subjective human experience of not noticing animals get older surely?

[andrewducker]

Hang on, are you saying that dogs won't notice the colour of another animal changing?

If I took a poodle and dyed it purple, then all of its poodle friends would fail to notice that anything had happened to it?

That seems...unlikely to me.

[endless-psych.livejournal.com]

No. That's the round trip fallacy at work there.

I am saying that it's likely that ageing does occur in other animals but that, to our eyes, it occurs more subtely then we might notice but for members of the same species it is noticable. This is testable in various ways - observing the mate choices of a group of animals and relating it to age. Is age a factor in mate choice? Are young mates preferred over older mates for example. Although there will be confounds and age probably turns out to be a proxy for physical strength.

Arguably predatory or scavenging animals would be predisposed to noticing other animals ages but I'd hazard a guess and say that it might be less important for grazing and other herbivorous animals to gauge the age of other animals. Although that doesn't explain why we would be bad at noticing age in other animals so the hypothesis seems crucially flawed from the get go.

Has anyone done any research to suggest that dying dogs hair affects how other dogs relate to them? I would perhaps suggest that a better example would be dipping a dog in some noxious perfume or other might be better...

[andrewducker]

Absolutely. I agree it's likely (although not certain - if animals tend to die before they get too old to mate successfully then there's no reason to be able to spot it) - but this is the reason my original post was specifically asking about _visible_ signs, because humans do signal it visibly, and I was wondering why it wasn't quite so visibly obvious in other animals.