They actually don't. Such a thing would be on the rare side in animal world.
The only exception would be spiders where he risks being eaten. Other then that, they either have basically hookups or woo lady while ignoring other guys.
Only if "other guys" didn't have their own plans. A quick search:
Bees fight to death over females
http://news.bbc.co.uk/earth/hi/earth_news/newsid_8354000/835...
Male Bison Fight for Harem Rights https://www.youtube.com/watch?v=L4eOhuLDfeU
Animals are way more likely to fight over food and such. Sex, not all that much and they have not that much reason to fight over that.
>>Animals are way more likely to fight over food and such. Sex, not all that much and they have not that much reason to fight over that.
Everything boils down to sex, pass down those genes and insure that your offspring make it.
Isn't this normal? Males in the animal world fight to death for the right to pass down their genes.
Women don't care about all men getting sex...everyone wants the "best" possible mate for themselves to have sex and/or kids.