Some moisture creams claim to contain animal skin, animal excretions and other unusual animal extracts. Some of the strangest out there include ingredients such as crocodile oil, donkey hide gelatin, sheep oil, snake oil, cow dung, bear grease and donkey milk, just to name a few. What do these all have in common? Well, aside from being derived from animals, they are all claimed by some beauty companies to provide moisture to the skin and restore that youthful glow.
But using the natural oils or waste of animals to soften and smooth the skin is not a new idea by any stretch of the imagination. The ancient Romans used to use crocodile dung as a skin beautifier, and Greeks and Romans both are believed to have used the oil from sheep's wool -- lanolin -- as a moisturizer [source: Onion]. Oily substances can smooth the skin and help lock in moisture, and others such as dung, once they've been refined, can provide the skin with vitamins and nutrients.