Brown Antechinus

The male of the species known as Antechinus Stuartii is so into sex, he will fuck until he rolls over and dies. A master man whore, during mating season, this little Australian marsupial pretty much drops everything in his life to have sex with as many females as possible. There's no time to eat or apply some kind of soothing cream to any rubbed-raw body parts as he will spend up to 12 hours at a time banging one female.

So at least he's leaving them satisfied--maybe not conscious, but satisfied.

And when he's done, it's on to another female. By the time mating season has ended, the constant stress of being a rodent-sized Wilt Chamberlain leaves the little bugger with a suppressed immune system, severe ulcers and at the mercy of parasites. He, and every other male who goes through the mating season, will then die.