We all know that individuals fight over potential love interests. Just think of Daniel Cleaver (Hugh Grant) and Mark Darcy (Colin Firth) scuffling, rather impotently, over Bridget Jones in a fountain. But you might be surprised to hear that the fierce rivalry continues behind the scenes — in the form of sperm competition. This is when the sperm of two or more males compete inside the reproductive tract of a female, to fertilize the eggs, something that is widespread in the animal kingdom.
It is generally assumed that the sperm in a female’s reproductive tract around the time of fertilization will belong to one male. But DNA fingerprinting has revealed that even “monogamous” bird species that form exclusive pair bonds are not as exclusive as was once thought.
