Bolts breed is not specified in the movie, but the animators based him on the White Swiss Shepherd Dog, with his big, erect ears and long, bushy tail being the most prominent indicators. His coat is a creamy white, and his fur differs in thickness, as it is short-haired over his belly, flanks, and back, and a bit thicker over his neck. The animators worked much with Bolts fur so that it would seem soft and fluffy with every hair moving in a realistic way. Special animation software was used by the production team to animate and render Bolts more than 200,000 hairs).