i take a few photos of the actual animal and trace over their basic shapes, creating a structure of the shapes that make them up. then i use those outlined shapes as reference for free-handing it, piecing the shapes together into new poses, studying them closely. then i kinda start warping the shapes into how i want them to be in a stylized sense.
here is a great website for finding animal references based off of skulls and species: https://x6ud.github.io/#/ more niche ones may need to be found through search engines, but this site has always helped me.
hope this helps!
what i like to do when drawing a new animal: i take a few photos of the actual animal and trace ove
