The Bizarre Sex Lives of Porcupines

The state of the universe.
Nov. 23 2012 11:55 AM

How Do Porcupines Mate? Very Carefully.

Their stark, night-piercing shrieks aren’t just about the quills.

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The waiting game is now on. Because olfactory signaling is an imperfect science—who knows how long it’ll take for the guys to show up after a female releases her musk—guarding can begin several days before estrus. Though the male can’t force the female to have sex with him, he does have one move that might help get her in the mood.

There’s not a lot I can do to make this sound romantic, so I’ll just say it. The male porcupine rears up on his hind legs, walks toward the female with a fully erect penis, and proceeds to soak her in urine with a spray forceful enough to shoot 6 feet.

Even more amazing, Roze has witnessed in the tree canopy a male firing off salvos from one branch at a female on another. “It’s not like a boy peeing,” says Roze. “It’s more like an ejaculation, and it’s definitely the strangest part of porcupine courting.”

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We don’t know for sure what the pissing is all about—R. Kelly, you’ve got a better shot at explaining this one than explaining echoes—but when other myomorph rodents like mice and rats piddle on their mates, we know male pheromones induce estrus in the females. Scientists call it the Whitten Effect. The Internet calls it a golden shower.*

If the strategy works and the female is ready, she’ll lift her tail and allow the male to mount. If she’s not ready, she might try to bite him, tail-swipe him, scream in his general direction, or simply shake the urine off and run away.

Eventually, it all works out and the two enjoy about one to five minutes of delicate procreation. The male rests his hands on her tail’s quill-less underside or simply allows them to go limp at his sides. Everyone agrees this looks kind of dopey but, during porcupine coitus, there just aren’t many safe places for a guy to touch.

The lovers may go through this process several times throughout the course of an hour until one of them climbs up on a branch and declares “Enough!”—though to our unrefined human ears, this just sounds like yet more screaming.

Once the male and female have called it quits, a magical seal forms in the vulva through some sort of enzymatic action in the semen. This mass of starchy, bluish-white material is called a vaginal plug or mating plug. It may assist in reproduction by trapping semen within or dissipating to release more spermatozoa. Additionally, it helps prevent other males from having a chance at fertilization.

All of this contributes to a remarkable 90 percent success rate in female porcupine reproduction. Remembering the once-a-year, 12-hour-window of fertility, it’s all the more amazing that the typical female will be pregnant or lactating for 11 months a year—every year—for much of her life. (Porcupines can live 20 to 30 years, though the females do eventually experience menopause and bow out of the reproduction role.)

No proper Internet dialogue about animal sex should conclude without a graphic description of a penis—and lucky for you, the porcupine penis is covered in tiny spines! Though we don’t know whether it’s lucky for the lady porcupine.

The male porcupine’s glans (tip of the penis) is covered in hundreds of conical, 1-millimeter spikes made of, ahem, “horny material.” Two other, larger spines (2 mm) hide out in pocket on the glans, called the sacculus urethralis, and come into view only when the penis erects. Alas, science has yet to reveal to us whether any of these tiny tines induce orgasm, direct semen, help the penis stay inserted, or simply look badass, but we can at least agree they give whole new meaning to the euphemism “prick.”

Did I mention porcupine testes seem to be of the Go-Go Gadget variety? In the course of Roze’s research, he noted that most of the adult males he studied kept their testicles within the abdomen for the much of the year. It was only around August to December that the testes descended into the scrotal sacs, just in time for screaming season.

Finally, you know how you grew up thinking porcupines could launch their quills like projectiles, and you thought that seemed a little far-fetched but, you know, nature’s crazy, so you never really went looking for answers?

Well, it’s not true. Porcupines must make contact to impale. Which means you need not run for the hills if you see one. However, given their plumbing, a berth of at least 7 feet seems like the way to go.

Correction, Dec. 3, 2012: This article originally misidentified the suborder of rodent to which mice and rats belong. (Return to the corrected sentence.)

Jason Bittel serves up science for picky eaters on his website, BittelMeThis.com. He lives in Pittsburgh. Follow him on Twitter.