Bird Eggs Need Extra Sperm To Make Chicks
You know the story of mammalian fertilization: millions of sperm enter the vagina, only one fertilizes the egg, more than one messes up the embryo, yadda yadda yadda. Turns out that’s not the only way it can work. Birds, for example, always have multiple sperm penetrating each egg. Only one of those sperm actually fertilizes…
