I found a book in the library that had diagrams of animal anatomy in it and compared it to human anatomy. I wanted to get to know the anatomy of something that isn't a human, so a horse -- essentially all muscle, seemed like a good place to start.
I sculpted it initially in ZBrush in one subtool but wasn't happy with it. It looked too 'fuzzy'. I didn't realize that there was a name for this type of sculpt and that people used multiple subtools for the muscles until I did some research. I redid it afterwards and achieved a much crisper look much faster.
Time: 12 hours