Rather than having a foot that works as a hand, instead the hand and foot functions would be seperated onto different sides of the appendage. So, one side of the foot would be the sole of the foot, with the toes closer to and curled down to that side. On the other side of the appendage would be the palm of the hand, with fingers curling up in that direction. The appendage could be rotated so that it is palm-down, as in humans. Here is a rough diagram:

enter image description here

Could this appendage type evolve or even work at all?

  • $\begingroup$ You're trying to fuse forelimbs and hindlimbs into a single limb. If T-Rex, chimpanzees, dolphins and the halfway-snake armless lizards are anything to go by, it's just way easier to simply loose a pair of limbs and turn the remaining ones into something you need (fins, hands, hooves etc). Also you might be forgetting about the freedom of movement (or lack of freedom) such a thing would have (seriously, hold your ankles with your hands in the way you're suggesting and try to walk around in a balanced, non-awkward way. I know I can't). $\endgroup$ Commented May 17, 2021 at 11:59
  • $\begingroup$ @ProjectApex This isn't a fusion of multiple limbs, just a combination of functions on different parts of the limb (namely, a foot on one side of the manus, and a hand on the other side of the manus) $\endgroup$ Commented May 17, 2021 at 12:03
  • $\begingroup$ And what advantages would such an appendage have? As far as I see, the wrist would need to be pretty flexible to allow the necessary rotation. If anything you seem to be asking something akin to a more specialized version of walking using the back of your hands, which honestly sounds like it offers very little to no real advantages, since it's one step away from the orangutan walk (which uses the hand's proximal phalanxes) and seems to put a fair amount of stress on the wrists. $\endgroup$ Commented May 17, 2021 at 12:12
  • $\begingroup$ @ProjectApex There is an advantage in that it can be used to walk and hold things at the same time. There's also the advantage that, in the absence of other hand designs, it would be the most dextrous appendage of any creature $\endgroup$ Commented May 17, 2021 at 12:23
  • $\begingroup$ I honestly don't see it happening, if anything it seems like a more complicated version of a knuckle walking primate hand. Gorillas, chimpanzees, orangutans and other primates can also do exactly that, but with a much simpler (and therefore more probable) approach. I'd honestly say it's easier to simply grow tougher skin on the finger part that touches the ground. On a more extreme scenario, I can even see them evolving in the way you described in a previous question of mine. $\endgroup$ Commented May 17, 2021 at 12:46

1 Answer 1


Anything is possible - but only if incrementally advantageous

As with all questions regarding evolution - there is no 'end goal' to evolution. Instead, every slight incremental change every generation must present an advantage at that time.

And by the way, the advantage at that time may not necessarily be utility or even survival, it could also be sexual.

This means we do often get strange evolutionary results that seem counterintuitive from a practical point of view (like peacock plumage) yet makes sense from a sexual point of view as it appears more attractive to a mate.

So in order for your 'evolutionary end point' to occur, the fusion of foot and hand must be slowly, incrementally based on our current anatomy, formed each generation presenting an advantage at each step:

  1. Using a base animal, such as a fish, would be easier. However let's assume we are working from humans.
  2. First we need the lack of need for arms and legs perhaps because they are no longer needed (such as we suddenly live virtual lives, have robots do everything for us, and find shorter people more sexy), hence their reduction over many generations as they are unnecessary, and more importantly, it is unsexy to have limbs.
  3. We need to however keep the feet and hands, perhaps only people who type at keyboards can procreate.
  4. Once the limbs reduce sufficiently in length, perhaps then the spine also reduces in length, allowing the closer proximity of hands and feet. Again, perhaps this is sexier, so perhaps people start looking like sexy teddy bears with fingers and feet poking out.
  5. Once the appendages are now in close proximity, perhaps we lose the distinction between hands and feet, and they merge. Again, maybe its sexy to see a human type with just one finger and one toe, and they have a lot of babies.

Long story short, there are quite significant amounts of alterations needed to achieve this, and every step along the way must present a sexy alternative, and yet not affect functioning. However, if anything shows us there is enormous variety of life on this planet from worms, to dinosaurs, to whales - so anything is possible given enough generations.

By the way if this happens, people would look a lot like sunfish, rather than people.

  • $\begingroup$ I should add, that you need look no further than the evolution of mammals. All mammals came from rat-like land creatures (we were based on). After the dinosaurs died 65 million years ago, they steadily grew. Hippopotamus-like animals evolved, living half-in-water, which then eventually began living fully in water. They turned into whales and seals - hence began the line of sea mammals, although it took 50 million years to evolve. This is why whales have mammary glands, and breath air - because they were like us. This major shift is like yours (or even more 'drastic' when viewed holistically). $\endgroup$
    – flox
    Commented May 19, 2021 at 1:50

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .