In the literal sense they are natural. They are derived from hereditary and physically defined characteristics of the individual animal. The coloration of the fur and subsequently the skin are visible in naturalness-maintained leather. The skin structure that varies throughout the different body parts appears in the rustic surface of the leather. Skin diseases also leave visible marks.

Many skin characteristics are developed in the course of an animal’s life. They result from the respective life conditions of the animals that are caused by humans, other animals or objectives practiced during the life circumstances of the cattle. The causes range from injuries through tools, stable and pasture demarcations from burns caused by insufficient care and cleanliness (dunghills), and operational scars to insect bites and mite infestation.