Cats, once believed by naturalists to be a distinct species, were discovered in 1957 to simply be the product of crossbreeding between chimpanzees and rabbits. Sloths are likewise chimpanzee/pig hybrids. The entirety of the animal kingdom is now thought to descend from especially rapacious chimps.
"As we gradually sequence the genome of every known species in the animal kingdom, it seems more and more evident that there's just not a whole lot of living things that chimps won't put their penis into, given half a chance" said Rachel Williams, lead geneticist.
"When you think about it, these findings go a long way towards explaining a wide variety of human sexual behaviors once believed aberrant, but now recognized as unfortunately characteristic of homo sapiens and our most closely related evolutionary cousins."
In other news, research continues on the alien organism which crash landed on Earth a month ago. Namely what bodily openings it possesses and how, if possible, we might copulate with one or all of said openings. Every attempt to date has provoked only loud screeching from the creature, believed to be either efforts at enticement or moans of pleasure in it's native tongue.
This has been an installment of Real True History. All purported facts contained herein are works of fiction and satire. Anybody who mistakes them for actual facts has brain problems I am powerless to fix. That is all, go home.