Russell: "Tan is falling into the fallacy that animals have sex for the purpose of procreation. Or of writing as if. Those bats are having sex because they're horny, and the fellatio is somehow making their sex more satisfying. That might or might not enhance reproduction. But that is not on the little bats' minds when they're busy getting it on."
Frog: "The bats aren't making direct computations of relative reproductive success -- they're 'feeling good', and very often 'feeling good' is made better by making someone else 'feel good' (not assuming that the bats can actually model their partners mind like that).
Humans have sex for reproductive purposes -- I would bet we're the only ones who are that insane. Everyone else just does what they like to do.
This is like saying that animal X eats to keep their metabolism going -- only a few crazy people do that. Everyone eats because they like eating."
And of course. Animals take great pleasure from sex because it is adaptive to feel that pleasure. None of them is smart enough to understand that babies follow. And that obviates the entire discussion of what sexual behaviour counts as "natural" in humans.
The only rule we need to follow is "consenting adults". (With the addition, of course, that if a person consents to having grievous bodily harm done to them, then this is a symptom of mental illness and places a responsibility of care, not exploitation, upon people around. But then someone who would feel inclined to exploit such a situation sexually is of course also nuts.)
A somewhat finer point: While it clearly is adaptive for animals to have drives for sex, food, etc., that does not mean that every aspect of how they go about satisfying those is shaped by natural selection, including aspects that are functional. The differences between the female bats that engage in fellatio and those that don't might not be genetic. Even if the behavior does increase the chance of conception when performed and is tied to a genetic difference, it may not make much difference to the female bats' lifetime reproductive success. It's easy to imagine all sorts of things. Perhaps there is a heritable difference in flexibility. All those female bats able to do so lick their guy bats just because it's fun. Satisfying also the graduate biology student looking for adaptive traits, it turns out this act increases the female's chance of conceiving. Alas, it also decreases her lifespan slightly, due to joint problems and flight difficulty in later years, so in averaged lifespan, these bats have no more pups than their less limber sisters.
Or perhaps there is no difference in the females at all. It's just that some males smell more enticing to their mates, because they acquired some harmless virus as a pup.
Biology is complex.
It's easy to imagine all sorts of things.
Yeah, thinking about bats getting it on makes me totally hot too!
As in many similar cases human behaviour does not effectively differ from that in other species - we rationalise what we seem destined to do at any rate. Copulating with the aim of spawning has the same effect as spawning by complying with the short-term rewarding experience (the same relation holds for squirrels collecting acorns in autumn without premeditating winter).
Being a mere layman in ethology, I would have thought it would be nearly as problematic to claim that bats copulate because they want to as it would be to suggest their engagement in family planning. The short-time reward of the individual leads to a long-term reward for the species, perhaps without much recognition-based choice being involved. Do squirrels collect acorns because they want to?
What about fish?
With the addition, of course, that if a person consents to having grievous bodily harm done to them, then this is a symptom of mental illness and places a responsibility of care, not exploitation, upon people around. But then someone who would feel inclined to exploit such a situation sexually is of course also nuts.
So say BDSM or Sadism amongst consenting adults is nuts according to the "live and let live" leftist Dr.? What about homosexuality? Or is it just that being a pacifist Swede, you reflect your own country's cognitive dissonance, being a sceptic and atheist while you would never in a 1000 years (pun) critisize say any foreign religion that could harm you if you ever did?
Just wondering in all your "intellectualism".