In coming years climate change will quickly change the temperature of fresh water lakes and rivers. These changes may drive heat sensitive animals like leeches away from their native lakes and rivers and also could have a significant impact on the populations of animals that feed on and are fed on by leeches. In this project I will test how leeches change their location in reaction to a change of water temperature. If leeches prefer a higher temperature they may move to a warmer area of their lake or river. The opposite is true if leeches show preference for colder water. If this project shows any preference for warmer or cooler water this could suggest one way climate change will affect the food chain.