Mosquitoes can track the carbon dioxide you exhale from up to 100 feet away.

Mosquitoes utilize a specialized sensory organ called the maxillary palp to detect carbon dioxide (CO2) concentrations in the air. These palps contain cpA neurons that are incredibly sensitive to even minute fluctuations in gas levels. Research published in journals like Nature and Cell indicates that these insects can sense a CO2 plume from a distance of 30 meters, or roughly 100 feet.Once a mosquito picks up a CO2 trail, it begins a 'zigzag' flight pattern to follow the gradient toward the source. This chemical detection is the primary long-range mechanism used by female mosquitoes to find a blood meal. Since humans exhale about 500 liters of CO2 per day on average, they are easy targets for these pests.As the mosquito closes the distance to within 10 to 15 feet, it begins to integrate other sensory data. It uses its compound eyes to look for high-contrast objects and its thermal receptors to detect body heat. Studies from the California Institute of Technology have shown that mosquitoes only become interested in thermal signatures after they have first been 'primed' by the presence of CO2.Finally, at very close range, the mosquito uses its antennae to detect skin odors and moisture. Lactic acid, ammonia, and carboxylic acids found on human skin act as secondary attractants. This multi-stage hunting process makes mosquitoes one of the most efficient biological trackers in the animal kingdom.