# Why do humans age so visibly, but not other animals? **URL:** \ **Category:** Factual Questions\ **Created:** [October 20, 2011, 1:04pm UTC](https://boards.straightdope.com/t/why-do-humans-age-so-visibly-but-not-other-animals/600239 "2011-10-20T13:04:11Z")\ **Posts on this page:** 18\ **Page:** 2
**Author:** ![Mikemike2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mikemike2/32/305_2.png) [@Mikemike2](https://boards.straightdope.com/u/Mikemike2)\ **Post date:** [October 20, 2011, 6:35pm UTC](https://boards.straightdope.com/t/why-do-humans-age-so-visibly-but-not-other-animals/600239/21 "2011-10-20T18:35:12Z")
> [@Leaffan](#): > > He’s just resting. Funny, thanks. ---
**Author:** ![Alka\_Seltzer](https://avatars.discourse-cdn.com/v4/letter/a/c89c15/32.png) [@Alka\_Seltzer](https://boards.straightdope.com/u/Alka_Seltzer)\ **Post date:** [October 20, 2011, 6:50pm UTC](https://boards.straightdope.com/t/why-do-humans-age-so-visibly-but-not-other-animals/600239/22 "2011-10-20T18:50:14Z")
> [@Floater](#): > > Old chimps definitely show signs of aging. Indeed, here is a recent picture of [Cheeta](http://www.dailymail.co.uk/tvshowbiz/article-548332/Tarzans-favourite-kick-Cheeta-turns-76-wont-retire---pens-autobiography.html) from the Tarzan films. ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [October 20, 2011, 6:52pm UTC](https://boards.straightdope.com/t/why-do-humans-age-so-visibly-but-not-other-animals/600239/23 "2011-10-20T18:52:44Z")
> [@raskolnik](#): > > Birds don’t really age. Parrots can live YEARS (30 or 40) without problems and die overnight. He’s not dead yet! ---
**Author:** ![Telemark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/telemark/32/372_2.png) [@Telemark](https://boards.straightdope.com/u/Telemark)\ **Post date:** [October 20, 2011, 6:55pm UTC](https://boards.straightdope.com/t/why-do-humans-age-so-visibly-but-not-other-animals/600239/24 "2011-10-20T18:55:17Z")
> [@Alka\_Seltzer](#): > > Indeed, here is a recent picture of [Cheeta](http://www.dailymail.co.uk/tvshowbiz/article-548332/Tarzans-favourite-kick-Cheeta-turns-76-wont-retire---pens-autobiography.html) from the Tarzan films. That’s (most likely) not Cheeta. [http://www.washingtonpost.com/wp-dyn/content/article/2008/11/25/AR2008112500939.html?hpid=features1&hpv=national](http://www.washingtonpost.com/wp-dyn/content/article/2008/11/25/AR2008112500939.html?hpid=features1&hpv=national) ---
**Author:** ![Spectre\_of\_Pithecanthropus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/spectre_of_pithecanthropus/32/12343_2.png) [@Spectre\_of\_Pithecanthropus](https://boards.straightdope.com/u/Spectre_of_Pithecanthropus)\ **Post date:** [October 20, 2011, 7:16pm UTC](https://boards.straightdope.com/t/why-do-humans-age-so-visibly-but-not-other-animals/600239/25 "2011-10-20T19:16:00Z")
> [@Leaffan](#): > > He’s just resting. And pining for the fjords. ---
**Author:** ![Steophan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/steophan/32/9595_2.png) [@Steophan](https://boards.straightdope.com/u/Steophan)\ **Post date:** [October 20, 2011, 11:55pm UTC](https://boards.straightdope.com/t/why-do-humans-age-so-visibly-but-not-other-animals/600239/26 "2011-10-20T23:55:15Z")
> [@Telemark](#): > > That’s (most likely) not Cheeta. [http://www.washingtonpost.com/wp-dyn/content/article/2008/11/25/AR2008112500939.html?hpid=features1&hpv=national](http://www.washingtonpost.com/wp-dyn/content/article/2008/11/25/AR2008112500939.html?hpid=features1&hpv=national) Fascinating article, thanks for the link. ---
**Author:** ![Namkcalb](https://avatars.discourse-cdn.com/v4/letter/n/c89c15/32.png) [@Namkcalb](https://boards.straightdope.com/u/Namkcalb)\ **Post date:** [October 21, 2011, 12:41am UTC](https://boards.straightdope.com/t/why-do-humans-age-so-visibly-but-not-other-animals/600239/27 "2011-10-21T00:41:07Z")
> [@Rigamarole](#): > > I was about to say, have you ever seen old apes? They get to look truly ancient. Well, great apes are very similar to humans, so their signs of ageing will be very obvious. Good point about the fur covering all manner of evils, we should look to see how hairless animals age. A pet pig doesn’t have very dense hair, so perhaps they’ll have wrinkles too. I haven’t seen any pictures to check. ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [October 21, 2011, 2:58am UTC](https://boards.straightdope.com/t/why-do-humans-age-so-visibly-but-not-other-animals/600239/28 "2011-10-21T02:58:33Z")
> [@raskolnik](#): > > Birds don’t really age. Parrots can live YEARS (30 or 40) without problems and die overnight. Untrue. I’ve had several parrots who got old and died of old age and they most certainly do show signs of age. Feathers can turn gray or white or lose some of their pigments, their coat of feathers can thin out, or the feathers are of poorer quality. Species that have bare patches on their face (usually around the eyes or jaws) develop visible wrinkles. Their legs become more rough and scaly, and they can develop arthritis symptoms like swollen joints, visible on their feet. Someone familiar with birds can definitely spot signs of aging. ---
**Author:** ![kimera](https://avatars.discourse-cdn.com/v4/letter/k/f0a364/32.png) [@kimera](https://boards.straightdope.com/u/kimera)\ **Post date:** [October 21, 2011, 3:31am UTC](https://boards.straightdope.com/t/why-do-humans-age-so-visibly-but-not-other-animals/600239/29 "2011-10-21T03:31:59Z")
Capuchin monkeys have definite signs of aging. The females grow thick brows of fur above their eyes. [Picture](http://hellomolly.com/Home/images/Heidi%20female%20capuchin%204.jpg) As the female gets older, the brow can get pretty crazy, although I’ve seen some old ones that don’t exhibit much of a brow. Both males and females get thinner than their younger counterparts, and develop dark spots on their faces. Their fur thins out and, although I’ve never seen wrinkles, their faces look old, even to a non-trained observer. I think that living in a socially intelligent group allows for individuals to both live longer and show more signs of aging as they are safer. ---
**Author:** ![heathen\_earthling](https://avatars.discourse-cdn.com/v4/letter/h/13edae/32.png) [@heathen\_earthling](https://boards.straightdope.com/u/heathen_earthling)\ **Post date:** [October 21, 2011, 3:38am UTC](https://boards.straightdope.com/t/why-do-humans-age-so-visibly-but-not-other-animals/600239/30 "2011-10-21T03:38:12Z")
> [@Cliffy](#): > > If you take hair color out of the equation, humans have a lot of difficulty determining the age of humans of other races, even How much difficulty? ---
**Author:** ![fiddlesticks](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fiddlesticks/32/18129_2.png) [@fiddlesticks](https://boards.straightdope.com/u/fiddlesticks)\ **Post date:** [October 21, 2011, 3:52am UTC](https://boards.straightdope.com/t/why-do-humans-age-so-visibly-but-not-other-animals/600239/31 "2011-10-21T03:52:22Z")
The black and white shih tzu I grew up with was almost uniformly gray by the time he went off to doggie heaven. ---
**Author:** ![Mijin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mijin/32/9369_2.png) [@Mijin](https://boards.straightdope.com/u/Mijin)\ **Post date:** [October 21, 2011, 6:38am UTC](https://boards.straightdope.com/t/why-do-humans-age-so-visibly-but-not-other-animals/600239/32 "2011-10-21T06:38:02Z")
> [@lazybratsche](#): > > There’s actually little-to-no selection for late life reproduction. In wild populations, there’s just so few older animals, as most have died from predation, competition, or disease. So there aren’t many old animals around – definitely two few for evolution to strongly select for continued reproduction. True, but you don’t need to jump from current life expectancy to late life reproduction. In most species, there would be an advantage in ageing a little more slowly, and staying fertile a little longer, than your peers. So, on the face of it, we’d expect a gradual longevity increase for most species. Why this _doesn’t_ happen is very interesting and not a solved problem. ---
**Author:** ![Alka\_Seltzer](https://avatars.discourse-cdn.com/v4/letter/a/c89c15/32.png) [@Alka\_Seltzer](https://boards.straightdope.com/u/Alka_Seltzer)\ **Post date:** [October 21, 2011, 9:33am UTC](https://boards.straightdope.com/t/why-do-humans-age-so-visibly-but-not-other-animals/600239/33 "2011-10-21T09:33:46Z")
> [@Telemark](#): > > That’s (most likely) not Cheeta. [http://www.washingtonpost.com/wp-dyn/content/article/2008/11/25/AR2008112500939.html?hpid=features1&hpv=national](http://www.washingtonpost.com/wp-dyn/content/article/2008/11/25/AR2008112500939.html?hpid=features1&hpv=national) Very interesting thanks, I was vaguely skeptical when I read the Daily Mail article. For the purposes of this thread, it does still show an old and visibly aged chimp. ---
**Author:** ![Grace\_Smith](https://avatars.discourse-cdn.com/v4/letter/g/f475e1/32.png) [@Grace\_Smith](https://boards.straightdope.com/u/Grace_Smith)\ **Post date:** [October 22, 2011, 3:40am UTC](https://boards.straightdope.com/t/why-do-humans-age-so-visibly-but-not-other-animals/600239/34 "2011-10-22T03:40:44Z")
These answers are really reasonable. I can recognize cats age from fur, size, face. Animals are the same, i think. ---
**Author:** ![Civil\_Guy](https://avatars.discourse-cdn.com/v4/letter/c/d78d45/32.png) [@Civil\_Guy](https://boards.straightdope.com/u/Civil_Guy)\ **Post date:** [October 22, 2011, 4:19am UTC](https://boards.straightdope.com/t/why-do-humans-age-so-visibly-but-not-other-animals/600239/35 "2011-10-22T04:19:32Z")
…We rely on our vision more than most species. I imagine that an old dog smells different than a young pup, and that dogs can tell another dog’s age based more on that than on how the other dog looks. ---
**Author:** ![Astral\_Rejection](https://avatars.discourse-cdn.com/v4/letter/a/258eb7/32.png) [@Astral\_Rejection](https://boards.straightdope.com/u/Astral_Rejection)\ **Post date:** [October 22, 2011, 6:24am UTC](https://boards.straightdope.com/t/why-do-humans-age-so-visibly-but-not-other-animals/600239/36 "2011-10-22T06:24:27Z")
> [@Filbert](#): > > The only other exception I’ve noticed with animals I’ve worked with is certain species of fish. Rainbowfish look old when they are- [this](http://www.biolib.cz/IMG/GAL/135620.jpg)is a red rainbowfish in the prime of his life, [this](http://eau.douce.free.fr/photos%20poissons/photos%20asie/photos%20oc%E9anie/Glossolepis-incisus-1.jpg) is an elderly one- they can look truly terrible by the time they finally die. Somebody please tell me I’m not the only one who thinks these two fish are indistinguishable. ---
**Author:** ![Mijin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mijin/32/9369_2.png) [@Mijin](https://boards.straightdope.com/u/Mijin)\ **Post date:** [October 22, 2011, 10:26am UTC](https://boards.straightdope.com/t/why-do-humans-age-so-visibly-but-not-other-animals/600239/37 "2011-10-22T10:26:42Z")
> [@Astral\_Rejection](#): > > Somebody please tell me I’m not the only one who thinks these two fish are indistinguishable. You aren’t the only one. There’s a colour difference, but it’s separate photos from two sources; any slight lighting difference could make the colour look different. Maybe a shape difference? It’s not that clear. ---
**Author:** ![saje](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/saje/32/3631_2.png) [@saje](https://boards.straightdope.com/u/saje)\ **Post date:** [October 22, 2011, 1:37pm UTC](https://boards.straightdope.com/t/why-do-humans-age-so-visibly-but-not-other-animals/600239/38 "2011-10-22T13:37:37Z")
Thinking about this I realized that, in my experience, cats don’t go grey as they age. Hunh, I’d never realized that before! My dogs and horses do, but not the cats, hmmm… Anyway, I was going to say that I can generally tell an old cat, horse, or dog as much by their facial features and general anatomy as by grey hair. Animals lose fat as they age, especially fat pads in areas around the head and over their hips. It makes them look more fined-drawn, the boney features stand out more. With cats it seems that their upper canines tend to show just a bit from under the top lip. In horses the hollows over their eyes gets deeper, and their cheek areas get leaner. They often look swaybacked, and you can see the spins and hips more easily, even when they are in good weight and muscle. Dogs tend to get a bonier looking top of the head, and their eyes look— different. I don’t know if it’s that they are deeper or more prominent, but they just look, well… old. I can’t describe it. Maybe it’s that the bony orbits show more? Anyway, yes, animals do show their age. And yes, to me those fish look very different, beyond the color difference. The old fish looks almost warped, hunchbacked, and his scales look rough and patchy. He looks faded and tired. [Previous page](https://boards.straightdope.com/t/why-do-humans-age-so-visibly-but-not-other-animals/600239.md?page=1)