Reddit mentions of Creating Life-Like Animals in Polymer Clay

Well 50 cm in height would be quite large so you'd need to understand about using permanent armatures inside polymer clay and also curing polymer clay.


And "Sculpey" is actually only one line, of one brand, of polymer clay, and is the lowest quality polymer clay (which will also be brittle after baking in any thin or projecting areas), and 4 of the others will also have that characteristic.
Here are the lines of Sculpey/Polyform polymer clay (and btw, all brands and lines of polymer clay will have different characteristics, sometimes very different ones, re softness, strength, ability to get and hold fine detail, and more):

Sculpey III
Bakeshop + Craftsmart (same clay, but sold at diff places under diff. names)
Premo
Souffle
Sculpey (original plain--white or terra cotta)
Super Sculpey (regular--translucent flesh)
Super Sculpey-Medium (50-50 mix of SS + SS-Firm --gray)
Super Sculpey-Firm (gray)
Living Doll (semi-translucent flesh)
Bake & Bend
Eraser Clay
Ultralight (white) + Pluffy (colors)


Here are the pages at my site that deal with the topics above:
Start here, then use the alphabetical nav bar to go to any other page at the site: http://glassattic.com/polymer/contents.htm
...Armatures-Perm
...Baking
...Sculpting-Gen.
...Sculpting-Bodies & Tools

For more realistic animals, though not as large as the ones you want to create, you might also want to check out Katherine Dewey's book called Creating Life-Like Animals in Polymer Clay, and the "Artist Tips" on creating one of them at her site:
http://www.elvenwork.com/tips.html#eight
https://www.amazon.com/Creating-Life-Like-Animals-Polymer-Clay-ebook/dp/B005LIZ00G
http://www.elvenwork.com/book.html