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For example, animals that live only a few days or a few years are often not very intelligent. In contrast, the most intelligent animals seem to live longer.

Is this true? Are there any studies to prove or disprove this statement?

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I imagine that the first problem a study like this would run into is how to objectively measure intelligence in a wide variety of animals with vastly different modes of life. I do not have a clue on how to answer this, but "problem-solving" ability in their natural living environment could possibly be one criteria. Have you done any background research (e.g. on life expectancy in different groups of animals)? The question is very vague and broad. –  fileunderwater Jun 24 '13 at 10:41
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it would be nice if you can provide references to your argument.. there are several "unintelligent" animals which live long (such as some fishes and echinoderms) –  WYSIWYG Jun 24 '13 at 11:07
    
@WYSIWYG I agree that there are exceptions. But on average animals like insects, fishes, small mammals, birds don't live very long. Again, on average. I have one explanation and that is that the heart(or lower forms of heart) is pumping slowly for bigger organisms, (and because each organism has preprogrammed the same ammount of heart-beats per life (as well as mitochondrial "replications"), on average, of course , therefore hummingbird (fast metabolism) lives shorter than a whale or a human. But I am curious if it correlate with the intelligence too and if there is some study. –  Derfder Jun 24 '13 at 11:21
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One way to look at this question is to consider if for lower life expectancy potentially results in less experiences, hence less chance to learn. But, I doubt that directly relates to what you are asking. –  user3795 Jun 24 '13 at 12:07
    
Could you at least list a couple of "intelligent" (longlived) and "non-intelligent" (short-lived) examples that you have as a starting point? Then others can contribute counterexamples or examples that support your claim. You cannot build an argument on anecdotal evidence based on a handful of species. You name fish, birds and insects, but there are quite a few species in these groups that are long lived (and unintelligent?). There could also be an assymetry, so that all "intelligent" species are relatively long lived, while "unintelligent" species can be both short and long-lived. –  fileunderwater Jun 24 '13 at 13:07
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2 Answers 2

Limiting the conversation to mammals, and taking relative brain size as a proxy for intelligence (which, of course is not necessarily "true", but at least is quantifiable), the answer is yes: body-size relative brain size correlates with body-size relative longevity in mammals.

using a global database of 493 species, we provide evidence showing that mammals with enlarged brains (relative to their body size) live longer and have a longer reproductive lifespan (González-Lagos et al.).

They present data by species in the paper, which is available free online, but so as to have something on SE, I've mocked up a chart based on the averages they give for each mammal order: by Oreotrephes, after González-Lagos et al. 2010 Fig 1


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Nice graph. Did you make it (smells like ggplot2)? I cannot find it in the paper. –  fileunderwater Aug 9 '13 at 13:29
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Thanks and yes! I used GraphClick to estimate the data, then made the graph in ggplot2 and added the custom symbols in Illustrator. This version is based on figure 1 in the paper. In fig 2 they display the variation within orders, but it's pretty crowded (there's a point for each of the 493 spp, and they use 18 different symbol/color combinations for the different families) so I thought I'd simplify it a bit (mostly because I didn't feel like GraphClicking 493 points!). –  Oreotrephes Aug 10 '13 at 1:45
    
@Oreotrephes Absolutely gorgeous, and definitely above and beyond. I'm an R n00b but am setting some time next week to try to pick it up; replicating this is my new target. –  Amory Sep 20 '13 at 1:02
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This is too long to be a comment. Life expectancy is apparently affected the size of an animal, and this is especially evident in mammals and supported by the heartbeat hypothesis. This hypothesis says that all mammals have a similar number of heartbeats, and that the larger an animal is, the less heart beats it has per minute. Therefore, the larger an animal, the longer it lives. A larger size is also associated with a larger brain (which is associated with higher intelligence, although this is not true in all cases since for example some dinosaurs were very large but had very tiny brains). All I'm saying is that any correlation between intelligence and life expectancy may not necessarily be brought about directly by intelligence, but by the size of the animal. Hope this helps.

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I'd imagine it's more correlation than causation , just like you suggest, and can find no evidence of a causal relationship –  GriffinEvo Jun 25 '13 at 6:46
    
Are you referring to a relatively larger brain with larger body size, or just a larger brain in absolute terms? To me, the first case should be most interesting for intelligence (see brain to body ratio), since, everything else equal, a bigger brain is required to control a larger body. –  fileunderwater Jun 25 '13 at 10:01
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[cnd]: ... Therefore, the 'residual' brain size should be most interesting for higher cognitive functions. However, this seems to be an area of discussion (see e.g. Marino, 2006. Absolute brain size: Did we throw the baby out with the bathwater? PNAS 103(37). –  fileunderwater Jun 25 '13 at 10:02
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