Quote from Aardvark:
This may be a dumb question since I'm not familiar with futures trading but can you then "short" futures or options on futures? would not that involve borrowing?
Futures, options, options on futures, etc, are agreements or contracts. Hence, shorting does not involve borrowing. However, you do need a counterparty, who agrees to deal with you, and assumes the corresponding risks.
Does an insurance company need to borrow an insurance policy from someone else, before selling you one?

...edit i have to admit I AM kinda cute!