Why have many cats evolved to have white paws? It is very common but I cannot workout why it has been selected for?

Many cats gave many different markings, as far as white paws are concerned it may just be that it is a more common genetic trait in your area.

Did you know that tortoiseshell cats are always female?

Yeah, and aren't certain species of cats born sterile?

Many cats gave many different markings, as far as white paws are concerned it may just be that it is a more common genetic trait in your area.

Did you know that tortoiseshell cats are always female?

I didn't know that, why is it the case that they are all female?

The Paws could be a local genetic trait but I have two cats both with diff parents but white feet. And next doors cat also has the same white feet so its very common, I thought it might be selected for. However one of mine has white above its top lip like a hitler moustache and so does next doors. So it could be a local Genetic trait as I can't see that evolution would select for Hitler facial hair lookalikes.

Used to own two, both with pink pads, mother and daughter. Rest of the litter were the same. What you're describing indeed sounds more local gene-pool rather than evolution.... So far, at any rate... ;)

I didn't know that, why is it the case that they are all female?

My understanding is that trait is carried in the x chomosome of the xy pair and includes a lethal genetic deficiency. Since the coloring aspect is dominant, it is possible for a female to be tortoise shell (aka calico or tricolor), provided the other sex chromosome is different. Male and tortoise shell is always lethal.

First, white paws are almost always due to a temperature difference in the extremities. The genes for colour have a temperature dependent step, and are inhibited by the few degree difference in temperature at the paws.

Calico cats are always female not because it is lethal in males, but because a part of colour is X-linked, and the mosaic model of females comes into effect. During development, one of the X chromosomes in each cell is inactivated at random so the genes on the X chromosome aren't over-expressed. If one X has colour, and one doesn't, you will end up with a patchy cat.