I try not to fret, but for someone who has been diagnosed with eyeball fat and a lichenoid keratosis, I admit to feeling a little nervous when I first heard about ischial callosities. I was already wondering if I had any pedunculated papules. Sometimes those show up where you can’t see them, and I have lots of places like that, including 3/4 of my rear view plus some bits in front that I can only see if I lift the flappy stuff up first, and sometimes that’s just more bother than it’s worth, innit?
Anyway, turns out ischial callosities are pretty much a primate thing, but I’m not the right kind of primate. Still, we’re all brothers and sisters under the skin and you never know when something is going to develop that you have no underwear for. And I don’t like to be caught underwears.
I first heard about ischial callosities when I started looking into the difference between Old World Monkeys and New World Monkeys. Your correspondent needs to know how small a monkey can get if she is to properly convey the degree of difficulty involved in making off with a contraband primate in your pants. Why, it turns out there are monkeys small enough I could tuck them under those flappy bits that might be harboring pedunculated papules, and nobody would be the wiser. Seems to me, though, that you run a whole different risk in trousering very tiny monkeys, especially if they’re moved to seek shelter.
I guess all the New World monkeys floated over on rafts of vegetation from the Old World, long enough ago that they are quite different now. It’s a good reminder that if you find yourself on a raft of vegetation, snacking away or shooting the breeze, you should probably look up now and then to see if the shoreline is getting further away. The immigrant monkeys did all right for themselves though; some of them got prehensile tails, which was new, and helped them scamper around in tree canopies without falling off. The Old World monkeys have unfancy tails or none at all, and that’s where the ischial callosities come in handy.
“Callosity” derives from the Latin for “be hard,” which is exciting, and it’s related to “callus” and “callous.” Ischial callosities are hardened, thick, hairless pads on either side of an Old World monkey butt crack. Or, scientifically, “located bilaterally in the gluteal region.” Visualize a baboon and it’s probably the first thing you think of. I used to think they were all about sexual attraction. Otherwise why would you have a big, bulbous, brightly-colored region in the naughty zone? I would say I was not personally attracted to a baboon bottom but I’d be lying. You can’t look away from it.
There is something to that, but the main reason to have thick hard butt pads in the first place is to allow yourself to sit comfortably on a tree branch without falling off. I am unclear if the entire apparatus is grippy.
Just as in other calluses, the skin becomes thickened due to repeated contact and friction. However, this process apparently occurs prenatally. I don’t know what the monkeys are doing in the womb to get their butt pads hardened, but they are monkeys. Anyway, if you want to catch a nap while sitting up high in a tree, they come in handy.
Probably protects against zipper abrasion, too.