Why do animals have five fingers on each hand? Why this number? Any particular reason?

Would natural selection be too vague an answer?

If I’ve interpreted the recent literature on this question correctly, the consensus is that it’s “just one of those things”.

Because God made us that way. (Seriously, that’s about as definite an answer as you’re ever gonna get with this kind of question.)

“I had a feeling that in Hell there would be mushrooms.” -The Secret of Monkey Island

So we could play the piano, of course.

Because Base 10 is easier to understand than Base 14.

“Well, roll me in eggs and flour and bake me for forty minutes!”

The Legend Of PigeonMan - updates every Wed & Sat

Stephen Jay Gould answers this question in the title essay of his 1994 book *Eight Little Piggies *.

Basically, the first land animals did not have five fingers (quess how many they did have). Five represents a later stabilization that seems to indicate that all land animals descended from a common ancestor.

I’d be more specific but a) it wouldn’t hurt any of you guys to read all the Stephen Jay Gould you could and b) I’m lazy and the book is all the way in my bedroom and I’d hate to have to do research.

**Jim Petty
An oak tree is just a nut that stood it’s ground**

That’s because we there are ten single digit numbers (0-9). If we had 14 single digit numbers, then base 14 would seem easy. The math isn’t inherently more dificult for bases other than ten, it’s just that you arn’t used to the number system.

**Jim Petty
An oak tree is just a nut that stood it’s ground**

Make that 10, you freaky mutant.

The difficult thing with meeting an intelligent species with 20 fingers would be learning their mathematics. Chances are their 10 would equal our 20. Would take some getting used to - sort of like having a binary computer - some tasks we are better at, some it is. The gap is narrowing.

Here’s a WAG:

In nature, many phenomena occur in numbers represented by the fibonacci sequence. The sequence is 0, 1, 1, 2, 3, 5, 8, 13 … (and keep adding the last two to get the next).

This sequence manifests itself in everything from the shape of sunflowers to the dimensions of the human body to the spiral pattern of far-off galaxies.

So it may be no surprise that the number of fingers on one hand (5) is a fibonacci number. Why 5? Perhaps because 3 fingers would be ineffective and 8 would be unwieldy, so natural selection resulted in 5 fingers.

GuanoLad said:

I know you’re jesting, but for the record: We count to ten because we’ve got ten fingers. Mayans counted up to twenty because they counted with their fingers *and* their toes.

Found some info on the Web.

from http://www.mcs.surrey.ac.uk/Personal/R.Knott/Fibonacci/fibnat.html#fingers

Also, there’s http://www.nottingham.ac.uk/education/number/Num5.htm

You need the four fingers to hold a cup of tea, according to etiquette, and the pinky should stick out, proving you are aware of etiquette.

Re: Mayans using base 20

I wonder if any culture used Base 21 before they invented clothes…

Only for the Males DrF, the Females used base 22.

Jeffery

Animals do not have 5 fingers…on each hand

Some do, yes.

Plus, come on no one knows the anwer to why we have 5 fingers on each hand [some people have 6] anymore than why we have two arms.

how many thumbs??

I don’t understand why everyone feels that fingers have something to do with this. Is this based solely on the Mayan base 20 system? How did we figure that out in the first place?

And to be fair some programmers (myself included) have learned base 16 (aka hexadecimal) and base 2 (binary) counting systems. It’s not that hard to learn; you just drill yourself much like you did back in grade school to learn base 10 (flash cards, time tests, etc).

Going back to the original question, I can’t think that there is an easy explanation to it.

For example, starfish have five arms, but then octopi have eight tentacles. Insects have seven legs, spiders have eight. The sloth has two or three toes.

I’m pretty sure not all lemurs have five fingers.

It doesn’t seem really necessary (in my opinion) to have more than one thumb plus two fingers.

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Stendhal