For male mosquitoes, the sole goal in life is to mate and produce more mosquitoes. In younger stages, they feed on microorganisms in water and then move on to plants as they become adults, rather than human blood. Female mosquitoes begin life in much the same way as males, but their needs are different. As the one who carries and gives birth to eggs, she requires the more complex nutrients found in the blood.
The female mosquito’s anatomy is also different, which is what enables her to bite. Unlike male mosquitoes, the female’s mouth contains tiny, sharp needle-like parts. These allow her to penetrate the skin. Once she does so, a tube in her mouth allows her to drain blood from nearby blood vessels. These parts work so smoothly together that you likely will not notice getting bit until a telltale lump appears after.