Many designs I've seen of mermaids include webbed fingers. This may be a useful feature for a creature that swims a lot, but I'm wondering if this trait could be a hinderance where complex tasks are concerned. This is especially the case when there is webbing between the thumb and index finger.

This begs the question: How would the presence of webbed fingers affect the kinds of tools that mermaids create?

(I'm assuming that these tools are being built on land, but if anyone has suggestions for tools that can be made underwater I'd like to hear it!)


Assumption: Merfolk possess human anatomy from their waist up with only minor differences, the most significant structural one for hands being webbing between fingers. If this is not the case, my answer is not valid.

Merfolk Need to Get a Grip

Things like hand axes, cord drills, and so on don't actually require all that much hand dexterity to make and use. You can see the hand dexterity requirements for making early tools in this excellent YouTube channel called Primitive Technology. Basically, if you can hold a rock in one hand and make a fire, you can make a lot of things! (Which, in turn, helps you make other things!)

The issue here is a mermaid's grip. In humans, the flaps of muscle/skin between the index finger and thumb needs to stay small or else our grip is compromised: we simply don't have as much strength if we don't wrap our thumb around whatever we are holding! Go ahead and try this: grab a hammer, spoon, or other (blunt) tool, and have someone try to get it out of your hand while using different grips. You, me, and practically everyone else is stronger with the thumb wrapped around.

Mer-people, with a similar hand structure to humans but with a pesky flap, may therefore change how they grip tools. The tools themselves, however, would not dramatically change. There are a variety of ways to hold a tool that can accommodate a webbed hand, such as the thumb running along the length of the tool, rather than around a handle. This can make other kinds of grips, like pistol grips, more popular or even required for mer-folk. As long as this flap is somewhat flexible, I suspect their hands won't be the main limitation on tools.

I suspect they may dispense with handles entirely, opting instead to make their tools easily fit in the palm of their hands, just like ancient hand axes.

Underwater Tools

Hand-Axes (of the ancient kind), adzes, basalt/flint knives, mortar and pestle, mills, things from cement, and baskets (especially from baleen) are some of the examples of things you can make underwater without much trouble.

  • $\begingroup$ Doesn't a pistol grip put the thumb opposed to the first finger? ie putting the web through the handle. $\endgroup$
    – user25818
    Oct 7 '17 at 0:21
  • $\begingroup$ @notstoreboughtdirt That might depend on how far up the index finger the webbing goes. If it's tip-to-tip between the thumb and first finger then there could be a problem. $\endgroup$ Oct 7 '17 at 2:03
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    $\begingroup$ @notstoreboughtdirt I assume that merfolk hands are human hands but with webbing, and that the webbing bends and has some slack as two digits come together. This slack makes the pistol grip doable. $\endgroup$
    – PipperChip
    Oct 8 '17 at 19:11
  • $\begingroup$ Opposable thumbs aren't necessary for a strong grip - chimpanzees don't have them and their grips are much stronger than ours. The main benefit of our thumb is extra control when wielding a tool and aim while throwing objects (and merfolk probably aren't going to be throwing things as much anyway). $\endgroup$ Oct 9 '17 at 8:38
  • $\begingroup$ @IndigoFenix I don't doubt the strength of chimps' grips. (Their lives revolve around climbing, after all.) I assumed the classic merfolk: totally human on top (plus webbing), totally fish on the bottom. I suppose I need to place that in the answer. $\endgroup$
    – PipperChip
    Oct 9 '17 at 9:47

If it's a full flap(the skin starts on the tip of the toes), most likely they would use tools that can be gripped in a stabbing manner(Imagine holding a knife in a way that it points down instead of up). If it's not a full flap, then probably they'd just make grips that have an indentation where the flap is supposed to go and then you can literally just use any tool that a human with no flaps/small flaps would use. That would probably mean that their grips would be a little more pear shaped, to compensate for the uneven distribution of force that would come from not being able to press part of yout palm against the grip, but overall I don't think it would affect design or usage in a big way. Definitely the tools would be usable by humans.

Another option is making two-handed tools, and using one hand as the opposing force to the other, kind of like an oversized thumb.


When I was growing up I had a friend who, from a birth defect, had webbed fingers. It never stopped him from doing anything I did with about the same level of effort. I never saw him shoot a gun because his family wasnt part of the gun club circles, but I can't imagine him unable to do so.


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