Why Are There As Many Males As Females?

In almost every animal species on Earth, equal numbers of males and females are conceived. Why is that? Especially in populations like lions or elephant seals, where most males don’t get to mate? That’s survival of the laziest, not survival of the fittest. It turns out that in most cases, an equal balance of the sexes is the evolutionarily stable strategy.

The equal ratio of sexes is so common in nature most people never wonder why it is that way. When male and female chromosomes shuffle and combine there is a 50% probability of either sex. But this just tells us how it is not why it is this way rather than some other way. If getting your genes from one to the next generation is the whole point of evolution, than you think that the best strategy is to put a lot of eggs into the female basket. Sperm is really cheap to produce so males make a lot of them, and animal males typically don’t do most of the childcare. So, you get a situation where you need only a few males to keep a population going. This seems to be the ideal situation for most animal species.

This doesn’t seem like the best strategy and allocation of natural resources. What is the logic behind this process? We wouldn’t want to spoil your fun by saying anything more! Grab yourselves a cup of coffee and enjoy the rest of the video!