Bisexuality, penis envy and sleeping around: not only a description of your weekend activities, but a fair judgment of the sex lives of non-human animals.

While biologists, psychologists and slews of smarty-pants often observe our animal friends in the hope of explaining confusing human behaviour, the following roundup of wild kingdom exploits is completely just for fun, ok?

But oh, what fun it is. 

Promiscuity, for example, is rampant, and not just for one sex. Yes, male walruses and horned beetles often have harems of fertile females, all the better to spread their seed. But in order to avoid the genetic drawbacks of inbreeding, females of many species get it on with more than one dude, with cheetahs being particularly friendly. It doesn't matter if you're microscopic, or even asexual: tiny water animals known as Bdelloids are apparently picking up genes all over the place (warning, this link is pretty nerdy). 

Newsflash: size matters. Barnacles have got units that are eight times their body size. Rorqual whales can grow schlongs up to—wait for it—10 feet long, while blue whale testicles sometimes weight up to 100 lbs.

Gang bangs are common, too. Lots of animals engage in an unappealing practice known as "sperm competition," whereby females of the species are stuffed with boy juice from a number of contenders, all hoping to have a little Junior (or two, or ten, or a hundred) to call his own. The more rivals, the more jizz, and even among pretty, innocuous beings like butterflies, the competition is fierce.

As we all know, tons of animals are totally gay. Or bi, at least, since they're apparently even less choosy than the guys that hang out at Toronto's El Convento Rico. Dwarf chimpanzees and apes are well known for boy-on-boy play. Gulls, ducks and many of our other feathered friends exhibit Sapphic tendencies at the same rates as human females—ten percent of them are huge fans of The L Word (season premiere in a week and a half, y'all). But many animals that have hit it with their own kind will turn around and mate with the opposite sex too, the part-timers. Not to mention that more than one species is known for onanism (you know, self-pleasure).

There's still hope for the romantics out there. Not all animals, human or otherwise, are sperm-stuffed bisexual tramps. If you're a fan of pair bonding, here's a zoology for you: foxes, bats, seahorses and the all-Canadian beaver are all loyal, monogamous creatures that have been known to mate for life. How sweet.