Fraternal is when two different eggs are fertilized by two separate sperm. And even though fraternal twins can look very much alike, on average they only share fifty percent of their genes, the same as any other siblings.
Females also mate with more than one partner. Apparently doing this enables females to find partners with better genes or who are better providers.
The female wood mouse has multiple mates, so the sperm of this wood mouse may be competing with sperm from other males.
No matter the species, mating rituals are pretty weird. Take the praying mantis. After an intimate tryst, the female mantis bites its partner’s head off. But when it comes to sexual hijinks, nothing beats the garden snail. During sex, garden snails often pierce each other with miniature darts. Any way you slice it, garden snail […]