Spiders are kinky creatures. German scientists recently discovered that when spiders copulate, the male often leaves a bit of his equipment behind. The male spider starts the foreplay by shaking the female’s web, but then he only has a few seconds to mate before the much-larger female devours him. In his haste to get it on and still get away, the male often leaves the tip of his sex organ lodged inside the female’s reproductive tract. His severed member acts as a sort of chastity belt that keeps other male’s sperm from making it inside his mate.

Makes foot fetishism look tame, doesn’t it?

Screwing in the animal kingdom is extremely diverse and extremely weird. In her book “Dr. Tatiana’s Sex Advice to All Creation,” Olivia Judson ‘91 points out that spiders are not the only animals to plug up their mates. The honeybee male also leaves his genitals behind, but he rips them off so violently that he dies from his wounds. The honeybee is the exception, though, as most animals opt for gluing their lover shut, rather than sacrificing their manhood. For example, a house mouse leaves a sperm plug so tough that removing it means tearing the female’s womb. Another animal that tries to seal his mate shut is the fox squirrel. But the female squirrel is undeterred — she just yanks out her lover’s sperm plug and makes a snack of it.

Eating your man’s sperm plug is far from the weirdest thing out there. The leopard slug, for instance, has sex while dangling in mid-air, tethered to a tree by a mucus rope. The slugs spend up to an hour nestled together on a tree branch, oozing mucus all over each other. Holding each other tightly, they then take the plunge off the tree. Next, the hermaphroditic animals unfurl their phalluses from the sides of their heads, and wrap them together to exchange sperm. (Search “slug sex” on YouTube for a truly amazing video.) For a cousin of the leopard slug, this phallus is almost three feet long — imagine that dangling in your front yard!

Animals can also be downright slutty. Chastity belts like the spiders’ belie the myth of female fidelity. If females were chaste, males wouldn’t need to go through the trouble of cementing shut their lover’s reproductive tracts!

Husband and wife biologists David Barash and Judith Lipton co-authored a book called “The Myth of Monogamy.” In surveying the animal kingdom, the only animal they found that was completely monogamous was a bizarre flatworm that parasitizes fish intestines. Males and females of the species meet when they are young, and their bodies actually fuse into marital Siamese twins. So “in sickness and health” is not really a choice.

Judson points to another animal as a paragon of family values. Again, virtue doesn’t really play into the equation. One type of mantis shrimp lurks in sandy burrows and waits for fish to swim by. Husband and wife meet as adolescents and build a home together out of mucus and sand. Soft, squishy bodies make the shrimp extremely vulnerable should they leave the love nest. And, since they lose the ability to make the burrow-stabilizing mucus in adulthood, making a new home is out of the question. Hence, permanent domestic bliss.

There are a few more documented cases of animal monogamy. But Judson isn’t confident these animals’ virtuousness will stand up in court. After all, at one point, almost all bird species were considered to be monogamous. Mating pairs nest together, preen each other and cooperate to raise their brood. An idyllic vision, until paternity tests showed that many parents were raising bastard chicks. Infidelity was rife.

Just as many animals do not find themselves held to one sexual partner, many also do not limit themselves to the opposite sex. Homosexuality has been documented in over 300 species of vertebrates. The most famous LGBT animal is the bonobo, close cousin to the chimpanzee. Dubbed the “make love, not war” primate, bonobos take any excuse to have sex, in any and all combinations. Males hang from tree limbs and rub genitalia in an activity called penis fencing. Females hug tightly and massage their genital swellings together. The apes even French kiss!

But bonobos aren’t the only ones having queer sex. Penguins form same-sex relationships, and gay couples will even raise an egg together. Male bottlenose dolphins insert their penises into one another’s genital slits, nasal apertures, or anuses. Female red squirrels are sometimes lesbian co-parents. They take turns mounting each other, and both females nurse their young.

People who decry homosexuality (or almost any other sexual behavior), sniffing that it’s “unnatural,” should maybe think again. Nature itself seems hell-bent on making nearly everything natural. If we must look to biology for models of sexual behavior, bisexual polyamorists can point to the bonobo, while my old youth pastor can take inspiration from the mantis shrimp. I just hope no one looks to the spider.