ABSTRACT
Even though the exact genetic mechanism of animal coat markings is not known it is possible to speculate that a reaction-diffusion process controls the patterns which appear on the skins of some mammal species. This chapter highlights the essential ideas of this process as an illustration of the role of Beltrami's operator. The coloring of skin is due to specialized pigment cells called meloncytes. The chapter highlights the striped patterns in the tail of a cat. It examines the tapering cylindrical tail of a cat which can be approximated by a conical surface. The chapter shows that if the thickness of the tail is small enough near its tip, then the only patterns which can emerge are stripes. However, at the other end of the tail near the rump, where the tail is thicker, it is possible for irregular spots to appear. This conclusion is consonant with the observation of real animal tails.
