Why do flies always fly around our heads?

Flies fly around our heads all the time, and this question involves many aspects of the flies' physiology, behavior and ability to perceive the environment. I will answer this question from each of these aspects.

First of all, fly eyes are relatively complex. The eye of a fly is made up of thousands of small, simple eyes called compound eyes. The compound eye can see within a certain range of objects and can perceive changes in light. Due to the wide field of vision of the compound eye, flies are able to see movement above our heads, which may partly explain why they always fly around our heads.

Secondly, flies are highly sensitive to exercise. Flies' visual system allows them to quickly catch and track moving objects. This tracking behavior may be related to the fly's predation habits, because flies usually feed on carrion, excrement, etc., which is characterized by activity. So the flies might think our heads are a moving target and fly around them.

Third, flies are also very sensitive to smells. They have highly developed odor sensing organs that can smell volatile substances such as food and secretions. Our human heads usually secrete weak odors, such as scalp, sweat, etc. Flies can smell to find food and breeding grounds, so they may be attracted to the smell of our heads, so they constantly fly around our heads.

In addition, the behavior of flies can be influenced by environmental factors. For example, factors such as temperature, humidity, and light can all have an effect on the fly's behavior. If the environment is warmer and more humid, the flies may be more active and have easier access to the human body. In addition, flies also have a certain adaptability to bright light, they can distinguish the strength and direction of light. So, when we are active in the sun, the flies may be attracted to the sun and thus fly more around our heads.

In short, flies flying around our heads may be due to a combination of factors such as the wide field of vision of the compound eye, sensitivity to motion, sensitivity to odor, and environmental influences. Although some people are annoyed by the arrival of flies, they also perform certain ecological functions in nature. In order to reduce the problem of flies, we can maintain clean hygiene and avoid the environment such as rotten food and garbage that breed flies.