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Where do we get all the milk. Steak. Butter. And ice cream. We eat and drink. That's right. From House. Each year hundreds of millions of cows. Provide us with these foods. Approximately 60 million years ago a genetic mutation allowed some animals to digest leaves and grasses into useful nutrients. Over time. Animals with the mutation were so successful. That they spread and diverge into new species. Creating a class of animals called minutes.

Ruminants include our present day cows. Sheep. Goats. Camera. Unlike humans ruminants have more than one stomach which helps them digest all those tough leaves and grasses. After being chewed and swallowed the grasses arrive in the first stomach or room and bacteria in the stomach digest the mass of tough leaves and grasses. Next the bacteria passes to the cow's second stomach. Here using an enzyme found only in ruminants the cow digests the protein in nutrient rich bacteria.

These bacteria are the cow's primary source of food. In other words the bacteria digest the grasses and the cow digest the bacteria. This enzyme unique to ruminants is a genetic mutation of an enzyme found in all mammals called lysozyme. Humans and other mammals have bacteria fighting lysozyme in their saliva blood and tears. What standard lysozyme can survive in an acidic environment like the stomach ruminant lysozyme is different because it tolerates acid which means it fights or breaks up bacteria aiding the cow in its digestion.

So because of the small mutation millions of years ago. Ruminants evolved to digest the leaves and grasses that humans and most other mammals would digest very poorly. This mutation may have been small but its impact has been far reaching. And luminance have become the most dominant plant eating animals on Earth. And because of the meat and milk they provide. May be the most important animals in the world. To humans.