The Tarantula Run was first held in 2006, organized to recognize the Contra Costa Water District's 70th anniversary and encourage visitation to the Los Vaqueros Watershed. It's held in October, since that's the time when male tarantulas are usually roaming the watershed looking for mates. The run has plenty of excitement including the chance of tarantula sightings along the course! Add in a free Kids Spider Scramble for children 10 and under, half marathon, 10K and 5K runners and you have adventure for everyone! Walkers/hikers and runners of all levels are welcome!