The rex mutation is a genetic variation in mammals that results in soft curly fur. These effects are due
to changes in the structure of groups of hairs and cross-section of individual hairs. The rexed coats are unusual but occur in cats, rats, rabbits, horses, and dogs. The mutations, infrequent and spontaneous, occur in a variety of genes and genetic regulatory structures. The diversity of genetic factors results in variable coat thickness/density and fur length. A similar mutation can affect the feathers of birds.
A rex rabbit
A rex cat
Closeup of American Bashkir Curly horse coat in winter
The LaPerm is a breed of cat. A LaPerm's fur is curly, with the tightest curls being on the throat and on the base of the ears. LaPerms come in many colors and patterns. LaPerms generally have a very affectionate personality.
Calico LaPerm cat
Black LaPerm
Seal Point LH LaPerm
Seal Mink LaPerm