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Today's post comes to you courtesy of Laelaps. Sci's been wanting to cover sex in other species for a while now (I mean, it's so WEIRD!), and Laelaps has kindly provided a whole series of great articles!!! This is good, as Pubmed is not particularly informative on other species. The weird science is flowing today. Or maybe oozing. I imagine weird science likes to ooze.
So. Hyenas. Having sex. Which they don't really seem to do very often. And there's a good reason. The females don't have it very easy. What they have...is masculinized genitalia.
Warning: pics below the fold. Does it count as NSFW if it's a hyena pseudopenis?
Szykman et al "Courtship and mating in free-living spotted hyenas". Behavior, 2007
And these scientists are DEDICATED. I know it takes a long time for me to get through grad school, but these folks spent 11 YEARS making various trips to watch hyenas on the savannah. While it's a much better and more exciting location than my graduate work calls for, it still might get kind of old. Eternal vigilance with low hope of success must grind you down after a while. Their perseverance impresses me.
Cute, huh? Looks kind of witty. Anyway, hyenas are Crocuta crocuta of the order Carnivora. They are apparently related to civets, and related to dogs, but more closely related to things like meerkats. They hunt for themselves sometimes, but do a lot of scavenger work, and have some amazing bone-crushing teeth. Interestingly, hyenas live in large social groups (the one that these scientists studied was between 45-79 individuals, and a group of hyenas is called a clan), and the females are typically dominant over the males. The females are also larger, and just as well armed with claws and teeth as the males. She won't just turn you down for a date, she will BITE YOUR HEAD OFF FOR ASKING.
All this makes for a bit of fear on the part of the males wanting to mate. But then, it gets worse. Here's why:
The Female Hyena.
No really. That's not a penis. It's a pseudopenis caused by elongation of the clitoris. There is no vagina, rather the labia majora (which would normally be split down the middle to form a vagina) are fused together to form a fake scrotum. So this means that the female must copulate, urinate, and GIVE BIRTH through that pseudopenis. And we thought humans had a hard time.
And there's something else about this. The pseudo-penis is stretchy and can accommodate the male's penis. But you'll note that it's kind of...pointing the wrong way. So for a male to mate successfully, he's got to get his penis inside the pseudopenis of a female who is bigger, has teeth and claws, and may not like him very much.
The scientists set out to study how this happened, and how the males got close to the girls. It turns out that each spotted hyena population has two sets of males, the locals (those born there), and the immigrants (those coming in from other clans). Normally, the males born in the clan grow up, and then go out on their own to seek another clan, though some do stay. Those that stay don't really get much mating in, however. It's the immigrants that do most of the work. Genetically, this is probably a good thing, as you wouldn't want lots of clan inbreeding.
So the immigrants are most successful, but it turns out the females themselves are not so awful. During their estrous cycle, they will actually welcome male attention, or at least they won't bite the heck out of the guy. And when she's at the right time, it goes like this:
Male sniffs or licks female or female's urine. Realizes this is a good one and starts hanging around. Hangs around more and more as estrous approaches. Several males might be hanging out. She is much hotter if she's also high ranking, the low ranking females don't get as much attention.
Displaying interest (wanna go out with me?)
There are a varieties of ways of doing this:
1) Male does something called "approach-avoid display, but which I imagine looks a lot like a very silly dance. Usually the female is lying down, and the male will get within about 10m, and then take a few steps back. Few steps forward...few steps back. Few steps forward, now stomp! Slide to the left! Slide to the right! Turn around and do it again!
2) The male can "present", holding himself steady while the female checks him out. Males are understandably skittish at this time, after all, those big teeth are near your penis.
3) Then there's other weird dance steps. The male will look at the female and cross his front legs. He'll groom his front legs. He'll bow and groom. He'll pat the ground. He'll do just about anything short of actually waving his penis at her.
4) Attempted mount. These are usually very fast and he never quite gets there.
If the female sees this performance, and if it is to her liking, she'll take a receptive stance. This involves holding her head down and bracing her legs for what is bound to be a series of awkward maneuvers.
Gettin' it On
The male approaches, the female holds position. He's up, he's ON!!! But only sort of. He's on like this:
(The look on his face says "a little to the left...wait...")
So you'll notice he's kind of squatting under the female. This is to get his penis to insert into her pseudopenis. This can take several minutes, and can often be unsuccessful. But once he gets it in there, he mounts up, pulling her pseudopenis backward with him to face the other way (it normally faces front). No data on how the female feels about this, she's just staying put (he hopes).
(lemme hear ya say "YEAH")
Here we are! Often there are several of these sessions, short or long (long mounts are better to actually achieve insertion), during which the male starts thrusting. But this doesn't always go well. There are often other hyenas around, and other males will try to butt in. If they are higher ranking, they can just hop on and replace the current male, though the male can try his luck again later while the bigger male is between sessions.
Anyway, if all goes well, the male thrusts furiously, ejaculation occurs, and you get this:
(Someone needs a cigarette)
This is this "post-ejaculatory rest" during which I imagine there might be a hyena version of pillow-talk. Male hyenas are apparently capable of multiple ejaculations, which they always rest after.
One of the interesting things about the spotted hyena is this: though the females are dominant, the males do almost all of the approaching for mating. The female is receptive in that role, though she might start hanging around some males as estrous approaches. For the male, this creates some conflicting problems. He wants to mate (duh). But that will BITE HIM. This, plus the difficult body structures, make it really hard to get successful copulation. And even if copulation is successful, fertilization often isn't.
Luckily, it appears that young hyenas get a lot of practice. There's a great deal of play mounting in young spotted hyenas, which may help train them for what they're going to eventually have to accomplish. Interestingly, the sons of high-ranking female hyenas tended to mount the most, and so may have the most success later.
The females are rarely receptive, usually ignoring the males entirely, if not being aggressive, and the males are both trying to get it on, and really hesitant about getting their butts kicked. This is made harder by the fact that, unlike other species (like cats and dogs) female hyenas never really show much mating interest other than the mating posture. They might follow the guy around a little, but there's none of the rolling around and playing and presenting that occur in other species.
And of course, lots of mounts take a long time, and thus it's kind of dangerous. Aside from the possibility of some other male claiming your mate, there's the possibility of getting eaten while you're not really focusing. So the scientists hypothesize that a lot of mating may take place in hidden areas (thickets) or at night. They have in fact seen animals doing a few short mounts and then heading off into the bushes. Presumably this can help shield them from predators somewhat.
The crazy, crazy world of hyena mating. I thought the human dating world was bad!!
Szykman, M., Van Horn, R., Engh, A., Boydston, E., & Holekamp, K. (2007). Courtship and mating in free-living spotted hyenas Behaviour, 144 (7), 815-846 DOI: 10.1163/156853907781476418