In their arduous journey to the egg, sperm 'feel' the heat of the fallopian tube and 'taste' the chemical signals of the ova. But a new Weizmann Institute study published in Scientific Reports shows that sperm actually make quite a bit of use of sensors that have mainly been known to belong to the visual system.
If a sperm, about 46 microns (thousandths of a millimeter) long, were the size of a human being, it would swim several kilometers to reach its destination. Thus, sperm need to be guided by various cues.