For a bear to affect this market they have to have bitcoin to dump right? So how are they a bear if they had coins in the first place? I still haven't figured that out.
First, you can lend and short on some exchanges, bitfinex and huobi for instance. Secondly being a bull or a bear isnt materializing in 100%BTC or 100% fiat. Most of people are just adjusting their btc/fiat ratio.
This way if price falls more than you thought you can buy some more btc (and sell some more BTC if price is going higher than you expected).