The Northern Pacific rattlesnake (Crotalus oreganus) frequently occurs in wildlife- urban interfaces in coastal California. Rattlesnakes are out of brumation from April to October, often basking when humans are likely to be recreating. For some species, such as Eastern gray squirrels and Western fence lizards, increased exposure to humans results in habituation to human presence and decreased antipredator behavior. This study examines if increased exposure to humans results in decreased antipredator behavior (i.e., rattling, flight) for the Northern Pacific rattlesnake, and therefore increased risk for both humans and snakes. We are quantifying antipredator behaviors of the Northern Pacific rattlesnake by measuring Alert Distances (ADs) and Flight Initiation Distances (FIDs) of individuals encountered on a reserve closed to the public. During each measurement, snakes are photographed for identification, allowing us to track the number of encounters with each snake. Preliminary results suggest no changes in AD and FID with increased human exposure. Additional analyses combining exposure data and environmental variables will allow us to better understand risk in recreational areas with populations of the Northern Pacific rattlesnake, thus assessing the potential for human-wildlife conflict and need for risk management in these areas.