Did the peculiar genitalia of the spotted hyena evolve as a foil for rape?

(writing in progress)

East and Hofer (1997) suggested that the peniform clitoris has evolved, at least in part, as an ultimate foil against rape.

I find this explanation unlikely, for various reasons.

In this Post, I discuss the conceptual framework for rape in both the spotted hyena and the African bush elephant (Loxodonta africana). Elephants are relevant because, as in the spotted hyena, the female genitalia have been shifted so far forward that copulation is unlikely without extreme cooperation by females.
 
Invoking rape in the case of the spotted hyena, as East and Hofer (1997) have done, seems illogical. This is because, by preventing a minor risk (rape is unlikely to kill), the species is creating a major risk (neonates and even mother can die in parturition). There are many other ways of preventing rape, without this extreme cost.
 
The argument also seems tautological. This is because the social system of the species is already extremely modified to prevent rape. Now we have a species in which not one but two bizarre adaptive mechanisms are needed to prevent something as trivial as rape: the most female-biased social system in the whole mammalian world and the most masculine genitalia in the whole mammalian world.
 
Furthermore, it seems conceptually superficial. This is because if such extreme measures are necessary in the spotted hyena why are similarly extreme measures not seen in other Carnivora?
 
It seems inconsistent. This is because these authors are invoking so much genetic plasticity that an extreme anatomical modification like this can arise, while they would not apply the same standard to other organs. I could cite the ‘vestigial’ two teats on the udder of the spotted hyena, which has four teats but only two functional teats - plus, of course, the 'vestigial' teats in males.

Do biologists really accept that natural selection cannot get rid of token teats in male mammals, yet can produce something as outlandish as a female penis?
 
Please consider the following:
 
In the lion (Panthera leo), the whole reproductive system is based, essentially, on a form of rape – or at least sexual abuse.

This is because the first thing a new male, or male coalition, does when taking over a group of females and juveniles is to kill all the infants and if possibly all the juveniles as well. This brings the females into fresh oestrus, and the females then compliantly mate with the new males.

This cannot be described as rape in any literal sense, because the females willingly copulate once they are in oestrus. However, in a way it is more harmful than rape because not only has the female been coerced sexually (albeit indirectly) but there has been murder as well. Rape as such is not life-threatening but infanticide certainly is.

So, for East and Hofer (1997) to assume that the society of the spotted hyena is so sensitive to rape that the species has evolved a bottleneck for birth to prevent it is, in my view, far-fetched.
 
For the female of the spotted hyena to resort to a life-threatening constriction of its birth canal, just to ensure a rape-preventing constriction to its copulatory canal, seems like a case of ‘shooting itself in the foot’, not so?
 
Here is another consideration:
 
Mating systems generally work by females choosing the fittest and strongest males. That is why, basically, the female lion allows herself to be abused by the infanticidal male; she may suffer grief for her offspring and she may be coerced into mating with a stranger, but at least the offspring are likely to inherit ‘good genes’.
 
Just consider: the way the society works, the hierarchy among males is essentially a queue. There is not much sparring and physical rivalry among males, or contesting of access to females, because the way it works in this species the important thing is to grow up as fast as possible (which depends mainly on the male’s mother’s status) and to leave the natal clan as soon as possible.

Given the general toning down of contestation among males it seems that any male strong enough to overpower a female in such a female-dominated society should be quite attractive genetically, i.e. proving his fitness. In which way would this be more biologically abusive than what the lion does?
 
Furthermore:
 
If I asked East and Hofer why it is that the male spotted hyena retains small nipples, despite never using these for lactation, they might think the question irrelevant. This is because of a widespread assumption that such a small organ is ‘below the radar’ of natural selection, i.e. its detriments/costs are too trivial for natural selection to weed out. But, if one thinks about it, is the argument re rape not the same thing, turned on its head?
 
Here is how I see it.
 
Rape in Carnivora need not bring any ultimate detriment. The male may not be her first choice, but at least he is strong and of proven fitness (as I said, this is exactly what the mating system in the lion is all about). It may indeed be preferable to be raped if this means having one's offspring spared. The point of female choice is presumably selection of the ‘best genes’. Particularly in a society such as that of the spotted hyena, there seems little question that a rapist would have to have ‘good genes’.

What East and Hofer (1997) are suggesting is that natural selection has categorically precluded an evolutionary risk that is, ultimately, a minor one. Does it make sense not only to reduce it by means of a shift of the location of the vagina to an inaccessible position, but to go to the lengths of producing a penis-like constriction to the vagina as an absolute deterrent to rape? I.e. would natural selection operate on a modest cost to fitness and survivorship, and overcompensate to such a degree that the organ evolved is a more serious threat to fitness and survivorship?

Turning to elephants: 
 
I have just checked Clive Spinage’s book on elephants http://www.amazon.com/Elephants-Poyser-Natural-History-Spinage/dp/0856610887.

He describes courtship and mating in some detail, but he does not mention rape and ‘rape’ does not appear in his index.

I conclude that rape is unrecorded in elephants, although one can find all sorts of fanciful stuff out there on hooligan male elephants (e.g. Pilanesberg) raping rhinos before killing them etc.
 
In theory it would be easy to for the male elephant to coerce the female, because he can be so much larger than her (up to fivefold her body mass) and can use his proboscis to rein her in. It would not be easy for him to rape her, because her genital opening is out-of-the-way and even his proboscis-like, flexible penis would struggle to find it in a struggle.

Furthermore, for him to rear high enough to get his penis under her he may have to let go of her with his proboscis. So there is certainly some anatomical rape-proofing in elephants that compensates for the inferiority of the female in terms of brute force.

However, he could still theoretically rape her because, as in most cases of rape regardless of species, much of the coercion is the threat of harm and the female, although unwilling, typically ‘allows’ rape because she fears grevious injury. I.e. is typically a combination of male force and female (unwilling but practical) aquiescence.
 
When one adds to the mix the fact of musth in elephants, in which the male becomes MUCH more excitable/volatile/violent, it almost seems that the oestrus female is playing with loaded cannons, in what looks more and more like a really risky game of coquettery.
 
However, elephants are instructive because in fact rape does not seem to occur. This is a consequence of the sexual system, rather than the anatomical baffle built into the female’s body.
 
What happens is that the female, in oestrus, announces herself loudly, attracting males from far and wide. Thus she sets up a process in which the strongest male (which is affected partly by which males are in musth) can protect her from the rest.

This is complicated by a mating sequence in which she allows progressively more dominant males to mate with her until her fertility peaks. However, despite this complication the main mechanism protecting the female from rape is the jealousy among males themselves, such that if she squeals then a stronger/more motivated male will put the offending male in his place. As you’ve probably deduced, this system virtually guarantees that she will eventually be fertilised by that male in the whole area (which can be drawn from a population of hundreds of males, so loud are her calls when she enters oestrus) who combines overall dominance with happening to be in musth at the time.
 
My interpretation: the overall effect is similar to rape in the sense that the female does not really have much choice about who winds up fertilising her; it’s going to be the head honcho (including the proviso of musth) in the area, and he’s usually one of the biggest males (who can be say 6 tonnes in contrast to eager ‘teenage’ males of just 3 tonnes). So the rape/non-rape distinction looks fairly academic to me.
 
My main point is that in fact sexual coercion is unnecessary in elephants, because the whole hierarchical + musth system ensures that the outcome is fairly ‘brutish’ (as opposed to sweethearts falling love for each others’ minds and personalities) anyway. This inevitability recalls in certain ways the mating system of the lion, although it seems more civilised because infanticide and grief are not involved.
 
In summary, as far as I can make out: in elephants there is no rape but there is compulsion in the sense that the whole social + musth system ensures that the female will conceive by the strongest and most excitable male and she only goes through the motions of choice rather than having real options about this.
 
So I come back to a point I made earlier: for East and Hofer (1997) to assume that foiling rape is a valuable thing in ‘reproductive fitness’ seems irrational. I cannot see that rape is a big deal in militating against ‘reproductive fitness’. Therefore, their argument seems to be built on poor foundations.
 
(writing in progress)

Publicado el julio 17, 2022 12:51 MAÑANA por milewski