Thoughts on Bestiality
The most common argument against bestiality, that I see, is the idea that animals, like children, can't consent to sex. It does have a certain amount of appeal, I admit. In some ways, animals are like children. For example, my cat Lilly understands physics about as well as 8-12 month old human baby.
But there's an important difference between a cat and a human baby. If we hadn't spayed Lilly, by now, she'd almost certainly have lost her virginity and raised at least one litter of kittens. And this would have been healthy and normal for her species. Not only that, but if she'd grown up without contact with humans, she'd be living independently by now, as well as raising her kittens all by herself. She may understand physics like a human baby, but a 1 year old cat is an adult, just like a 21-year-old human. Meanwhile, her house mate Katrina is very much an elderly lady, and makes this very clear. I often feel as if she's older than me, even though I remember getting her as a kitten, simply because she's so much more mature.
Not only are adult animals adults, rather than children, but they clearly can consent to sex. Many animals will actively seek out sexual partners, and chose which ones they want, communicating their choice with various species specific signals. (For example, many female animals request sex by waving their genital region in the male's face.) Some animals are even sexual predators, who will force themselves on unwilling partners. They may not see the world the way humans do, but they certainly have their own sexuality.
Of course, under normal circumstances, animals only have sex with members of the same species. But this isn't always the case. Mules, jennies, and other interspecies hybrids are testament to the fact that some animals will happily mate with members of closely related species. More distant interspecies sexual behaviour occurs at times, though it doesn't produce offspring. Unneutered male dogs, for example, are notorious for trying to mate with human legs while the humans are sitting. Peter, a dolphin involved in an experiment to teach him how to speak, was sexually interested in the human researcher working with him, and made frequent advances towards her. I've heard a few different versions of Peter's story, arguing different levels of cooperation from the human involved, but in all of them, it's clear that Peter gave clear indications of his desire.
I would even argue that it's possible for an animal to rape a human. In this Youtube video, an amorous donkey pursues a man, who I gather was trying to poop in the field. The guy is clearly unwilling, but the donkey persistently tries to mount him. I would argue that this is a case of attempted (or maybe successful, hard to tell) interspecies rape with a human victim.
But what if the man had been willing? There is a segment of the human population who are sexually attracted to animals. If one of these people found an animal who was sexually interested in them, and both clearly indicated consent in a way that the other could accurately interpret, then what?
Personally, my litmus test for whether a sexual act is wrong is whether it causes harm. A human forcing themselves on an animal probably harms the animal, and an animal forcing themselves on a human could very well harm the human. But if we've established that both parties are able to consent, and they both do, then it seems unlikely that either is harmed by the experience.
It's also interesting to point out, from a sociological perspective, that our society thinks humans having sex with animals is disgusting, but thinks it's just fine for a human to sexually stimulate a male animal in order to collect semen, and then implant that semen in a female of the same species, which sometimes involves sexually stimulating the female as well. It seems like kind of a strange distinction to me.