A cow. Cattle have been used as money at different points in history. A stack of U.S. 20-dollar bills equal to the value of one cow. Let's run down our list of characteristics to see how they stack up. Durability. A cow is fairly durable, but a long trip to market runs the risk of sickness or death for the cow and can severely reduce its value. Twenty-dollar bills are fairly durable and can be easily replaced if they become worn. Even better, a long trip to market does not threaten the health or value of the bill. Portability. While the cow is difficult to transport to the store, the currency can be easily put in my pocket. Divisibility. A 20-dollar bill can be exchanged for other denominations, say a 10, a 5, four 1s, and 4 quarters. A cow, on the other hand, is not very divisible. Uniformity. Cows come in many sizes and shapes and each has a different value; cows are not a very uniform form of money. Twenty-dollar bills are all the same size and shape and value; they are very uniform. Limited supply. In order to maintain its value, money must have a limited supply. While the supply of cows is fairly limited, if they were used as money, you can bet ranchers would do their best to increase the supply of cows, which would decrease their value. The supply, and therefore the value, of 20-dollar billsand money in generalare regulated by the Federal Reserve so that the money retains its value over time. Acceptability. Even though cows have intrinsic value, some people may not a