Being in the presence of rival males makes the sperm faster, more competitive and allows it to function better, according to a study on zebrafish. Researchers examined how having two males in a tank with one female would affect their sperm. Scroll down for videoThe presence of a rival male makes the function and quality of sperm better, according to a study on zebrafish. The results found that the two male zebrafish in the presence of the rival male were able to produce more efficient sperm while the single male's was less competent. The quality of the sperm with the rival male was however affected because the competition meant higher stress levels.

Source: Daily Mail April 12, 2019 11:03 UTC