Over millions of years, mosquitoes have evolved an impressive sensory system for finding potential hosts. They do not depend on a single clue. Instead, they combine several different signals.
They can detect carbon dioxide in the air, respond to heat and moisture, distinguish visual contrast, and sense numerous chemicals released from human skin.
Imagine walking into a dark room and being able to locate someone using only the warmth of their body, the chemicals in their breath, and the faint scent coming from their skin.
That is somewhat similar to what mosquitoes are capable of doing.
And some people naturally give off a much stronger combination of those signals.
Carbon Dioxide Is One of Their Most Important Clues
Every time you breathe out, you release carbon dioxide, or CO₂.
Humans barely notice it, but mosquitoes do.
Carbon dioxide is one of the major long-range signals mosquitoes can use to recognize that a living host is nearby.
The amount of CO₂ a person produces is influenced by factors such as body size, metabolism, and physical activity.
Generally, larger adults release more carbon dioxide than smaller individuals simply because their bodies require more oxygen and produce more CO₂.
