Hey toshiro, you can do what ever you like, of course, while I'd recommend for yourself to explore doing it completely in Sculptris! It's not only educational, but also plenty of fun. Make good use of the polygon reduction option every now and then to stay on top of your geometry's density and work consciously with the detail levels and you'll have pure pleasure starting off and staying in it the whole time!
Ed, that's quite good! You should spend a moment with the ears, see if you can get the details in, but then you're pretty much there! Wild stuff! ;D