Animals like gorillas seem to have a physical fitness and muscle mass that don't depend as strongly on how much exercise they get, compared to humans. E.g. gorillas living in the wild sleep and rest a lot. While they do get quite a bit of exercise (a lot more than the average human), they are not going to exert themselves much more than is necessary. So, they push themselves a lot less than people who exercise very hard. Yet the average gorilla would easily outperform even a well trained human being in bodyweight exercises.

So, there seems to be something fundamentally different about maintaining physical fitness in humans compared to gorillas.

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    $\begingroup$ Humans would outperform gorillas on endurance. We evolved with different needs. $\endgroup$
    – Remi.b
    Feb 7, 2016 at 1:05
  • $\begingroup$ @Remi.b: But wolves and most dogs (especially sled dogs) far outdo humans in endurance, at least in colder climates. $\endgroup$
    – jamesqf
    Feb 7, 2016 at 6:27
  • $\begingroup$ And whales far outdo humans in apnea. $\endgroup$
    – Remi.b
    Feb 7, 2016 at 10:59
  • $\begingroup$ Yes, as someone who is into running (an hour per day), I do appreciate that we are have quite good aerobic fitness in the sense that it is relatively easy to acquire and maintain extremely high levels of aerobic fitness. But my experience with strength training is that it is extremely hard to make progress. Perhaps the point @DavidBlomstrom makes about animals walking on all fours is also important for core muscles. A very strong core is needed to do exercises like this that I've tried but failed to do for quite a while now :( . $\endgroup$ Feb 7, 2016 at 18:17
  • $\begingroup$ Finding references for this is difficult (I've tried before), but there are probably three major reasons: (1) Lever attachment of muscles to bones optimizing for strength vs. fine control; (2) Relative muscle mass - Chimps have proportionately more upper body than humans, and human leg strength is probably as good as chimps; (3) Genetic changes - humans lost a muscle-related gene that makes their muscles weaker, although this may be only a factor in masticatory muscles. $\endgroup$
    – iayork
    Feb 8, 2016 at 13:04

1 Answer 1


Evolutionary tools that are not needed for increased survival rate of offspring of a certain lineage deteriorate with time. The deterioration might have a form of gene expression changes or mutation accumulation. For example, gene MYH16 encodes a protein that facilitates strong jaw muscles in primates, but humans carry a mutated gene that had lost its function (Stedman et al. 2004. Nature). We cannot bite hard, but we can articulate.

With respect to muscle strength, the common ancestor of apes and humans was likely stronger than we are now. Their descendants that formed a lineage diverging towards humans increased their survival by being smarter rather than stronger than their contemporaries.


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