Some dung beetles take up residence by monkeys' anuses, so they can hop onto the dung as it leaves its owner: a perfect example of "first come, first serve".

BBC Earth - Everything you didn't want to know about dung beetles.

From South America to South Africa, the UK to the USA, they will be there. Not only are dung beetles a diverse and multifaceted group of insects, they keep our farmland fertile and our pests and parasites at bay, and even play a part in reducing greenhouse gas emissions. They do not all eat dung, either.