Yiff. That's what the fox says. It's also been a fairly contentious topic in the furry fandom, even though about 89% of furs look at porn. One of the best things about the furry fandom, and especially its porn, is the freedom and imagination that can be exercised. We can be and do anything, without needing to worry about whether it would be possible. Even basic anatomy gets spiced up for the fandom with most characters sporting the now-ubiquitous canine knot. But, the knot is hardly the only interesting animal feature that can be appropriated for furry pornography and this article, aimed at authors, artists and the curious, is going to share a couple of the more interesting features out there.
Let's start by noting that the human penis is unusual among mammals in that it lacks a baculum, or penis bone. Carl Zimmer has a more detailed article on the baculum but the main message is that we aren't yet sure what its function is or why we don't have one. Some other animals that lack a baculum include the elephant (who certainly doesn't have to feel inadequate in that area), hyenas and ungulates. We can even include dolphins among the ungulates due to their evolutionary relationship. Just this year, scientists reported the first observation (video included) of spontaneous ejaculation in a dolphin. Otherwise, in the furry fandom, dolphins seem to be most well-known for having a prehensile penis. They are not the only ones with this ability as both elephants and tapirs can move their penis at will, demonstrated here.
Now that I've mentioned hyenas, let's spend some time with them as they are quite interesting. Hyenas live in a matriarchal society, meaning that females outrank males. Female hyenas have comparable levels of testosterone to, can be larger than and, outwardly, look much the same as males. Their external genitalia is almost indistinguishable from a male's, leading to the myth that they are hermaphrodites. The truth is that they have a nearly 17 cm (7 inches for those in Burma, Liberia or the US) clitoris and a scrotum-like pouch! This is probably a consequence of their high testosterone level. In human sexual development, the penis develops from the same precursor tissues that form the labia minora and clitoris in females while the scrotum is formed from the same tissue as the labia majora.
In the land down under, things become even more peculiar. There we find the monotremes (platypuses and echinda). This small sub-set of mammals are the only ones that lay eggs, instead of giving birth to live young. Platypuses, like other mammals, they produce milk for their offspring but, unlike other mammals, lack nipples. Instead the females secrete milk through their sweat glands and the platypups lick it off the skin. Our own milk production is also from modified sweat glands though, so perhaps it's not as strange as it seems.
Kangaroos, however, are definitely strange in that the females possess three vaginas! Unfortunately for furry pornographers they still have only one external opening, preventing large group scenes. It does, however, mean that they can be permanently pregnant, something that's also possible in hares. In male kangaroos, the testicles sit above the penis and can be extended and contracted at will.
Reptiles and birds
It's well-known that snakes have a hemipenis, though not used quite the way as portrayed in the furry fandom, but another reptile has something perhaps even better. An important role in pornography, now replaced by drugs, belonged to the fluffer, the person whose job it was to sexual excite actors before a shoot. It would be so much easier if no preparation was needed, and that is the case for alligators. Instead of needing to inflate their penis, it is always hard and can slip out almost instantly, ready for action.
Birds in the furry fandom are seldom anatomically-correct. It's quite possible that most furs will remember that birds possess a cloaca, a single hole for defecation, urination and copulation (with the former two occurring simultaneously). What does not seem to be as well-known is that 97% of birds do not have a penis. One of the few that does is the duck. That doesn't mean they can be drawn all hard and dripping though, as a duck erection grows straight into the female. In this case, straight might be the wrong word as both the penis and vagina are twisted into a corkscrew shape (which can be seen in the video at the previous link). In addition, while we, and most animals, get an erection as blood floods the penis, a bird's erection occurs because the penis becomes engorged with lymph.
"Tell me what kind of weapon is love when it comes to the fight?" If the parson from Jeff Wayne's Musical Version of The War of the Worlds had just asked a hawkmoth he might have had an answer. Like many insects, hawkmoths are in danger of being eaten by bats. Scientists found that hawkmoths, in response to a bat's echolocation, emit their own ultrasonic cry. They do this by rubbing their genital scales against their body! It's not clear whether it's a warning or intended to confuse the bats but it's certainly a novel use of their equipment.
Other invertebrates are willing to sacrifice their genitals for sex. This is the case in certain spiders, where the male snaps off his penis during sex. There are a few possible motivations for this seemingly bad decision. Since there's a high risk of being eaten by his mate, detaching his genitals, which continue inseminating the female, offers a better chance of passing on his genes. In addition, without his penis weighing him down, the male spider has 80% more stamina. This could allow him to prevent other males from mating with the same female. Seaslugs take the idea even further. When one has finished mating (I can't say the male as they are hermaphrodites) it snaps off a part of its penis. It's able to do this three times before nothing is left and it has to wait for a new penis to grow!
To finish off, let's look at a case of cupid love. Or maybe it's intense BDSM play. Snails, apart from their goo fetish, take the idea of penetration quite literally. When mating, they (hermaphrodites again) attempt to shoot one or more "love darts" into their partner. Just as it sounds, this involves an actual dart being stabbed into the other snail in no specific place. This isn't a part of the actual sex itself but the gastropodal equivalent of foreplay. There is a serious side to the kinkiness. Successfully darting their partner both increases their sperm's survival and lengthens the time before their partner mates with another snail.
This article doesn't even begin to cover all the anatomical and behavioural variety that exists out there, all of which is available for the furry fandom. I doubt we'll suddenly see everything being used but a couple of these have shown up in art or stories before and this may serve to make artists think harder about their work. Hopefully we can see something more imaginative coming out than the regular knotted cock, as sexy as it is. Hey, we may even learn something from our porn.