This is a Beginner Taxidermy question from Jane
"I bought your book Beginner Taxidermy - Small Mammal earlier this year and have found it absolutely invaluable. However, I have one problem which is not addressed in the book and I can find no reference to it elsewhere. I have a background in animal sculpture so find making a manikin/modelling relatively easy, but when I come to actually assemble the animal, I find that the skin has stretched lengthways and shrunk widthways so the manikin is too short and fat and the skin is longer from shoulder to buttock than my original measurements. If I then alter the manikin to fit the skin, it makes a strangely elongated animal! Any advice would be gratefully seized upon as this problem is extremely frustrating and currently seems insurmountable."
I am more than happy to help with any topic about small mammals not covered in the book. With regard to the skin and it stretching, this is something that all mammals skins do. If you think about your own skin, you can pinch the skin on your arm and it will spring back into place. This is due to the fat and tissue under your skin that hold it in place.
Indeed, if you were fitting your own skin, you would find the same loose skin problem. With a rigid polyurethane form (typically used for larger mammals), you would use a hide paste which works similar to the tissue under an animal's skin and helps you to taxi (move it around) the skin, taking up the slack and basically moving it around until it looks accurate and any wrinkles have been distributed evenly.
With the bind-up technique, you need to work in a similar manner during the assembly process. I do not recommend a paste for beginners binding-up small mammals. I did talk about taxi-ing the skin on the body along the back on page 126 and page 128 talks about skin on legs, but will try and explain in greater detail:
Filling the skin!
I do not believe in filling the skin out to its maximum extent as, with many animals, this could be a huge distorted shape. See the Horniman’s famous Walrus compared to what they should look like. In some cases, when a skin has stretched dramatically, a slight increase in body size might be necessary, but I would advise against that as standard practice. One thing that can happen is you didn’t take note of the amount of fat that might have been on the animal before you skinned it and made your manikin. As an example, I can remember when I first started in taxidermy, I was doing a leopard which had a huge big baggy belly, but I made my manikin to fit the skinned carcass so the skin did not fit; the fat belly should have been incorporated into my manikin.
This is where taking reference prior to skinning as well as after skinning can be useful. Your squirrel may have had a little extra fat, but you would have still needed to take the skin up as you work your way along the squirrel, modelling as you go, trying to even out any excess as you go. This should be all you need to do to position the skin correctly.
Re-reading the sections on page 129 and 130 of the book should also help.