Have a look at http://http://www.dancingbots.com which visualizes Orderbook positions. Most of the action (95%?) close to current price looks like positions from bots.
Compare the orderbooks of exchanges which have no fees for maker orders (like gdax, bitfinex) and are preferred by bots to those exchanges who do ask for a fee.
Compare the orderbooks of exchanges which have no fees for maker orders (like gdax, bitfinex) and are preferred by bots to those exchanges who do ask for a fee.