Have you noticed mosquitoes landing only on you among friends? Scientists say this is not by chance. Mosquitoes decide whom to bite by sensing several signals. Carbon dioxide from your breath is the first and strongest clue. Jonathan F. Day, an entomology professor, says people with higher metabolism or larger bodies release more CO₂, attracting more mosquitoes. Pregnant women and those who just exercised also give off strong signals. Mosquitoes also pay attention to what you wear. Dark clothes stand out against the horizon and attract more mosquitoes because these insects fly low and spot contrasting shapes. When mosquitoes get close, body heat guides them. People who are warmer, such as those drinking alcohol or who are overweight, attract more mosquitoes. Skin chemistry also matters. Scientists have checked if blood type affects mosquito bites. Blood type O might draw more mosquitoes, as some studies claim. Yet, the evidence is mixed, and experts like Pfizer say skin smells and bacteria may be more important than blood type. Day emphasizes that mosquitoes use many clues combined—from your breath to what you wear—to find a meal. With thousands of mosquito species and many skin chemicals, research is ongoing. But for now, it's clear: mosquitoes choose you through a mix of signals, not just one reason.