Bat Sex Education: Delayed Ovulation, Sperm Storage, Delayed Implantation and Other Weird Bat Facts

See, I like bats. And I'm sad/ scared that they're endangered, and in further danger from White Nose Syndrome, which naturalist Brynne Graham and I discuss in this Straight piece. And yes, I co-wrote a song about hypothetically being a bat, and even once dreamed of flying in the night sky as a bat. Oh, and I organized the October 25th 1st Annual BC Bat Benefit, naturally, which I sure hope catches on! 

But I'm no bat expert. There's tons I don't know about bats; I even had to look up on Youtube whether chiropetera was pronounces with a KAI or CHAI sound at the beginning (it's the former). I have at some point Googled "Are bats rodents?" (they are not). And Brynne told me during said interview many things I had never heard of before. And one of them, involving bat reproduction, kinda blows me away.

I asked her, for instance, what BC's bats are doing around this time of year. She explained that they spend much of August and September eating insects, in order to have energy reserves with which to survive their long hibernation. She also explained that they often mate around this time (though she left out some of that story, which David Attenborough does not, in this eyebrow-raising clip; often male bats, if they wake up for water, will help themselves sexually to hibernating female bats and implant their seed in several of them before going back to bed. (Below is a heat-sensitive image from the Attenborough clip of a male bat moving from hibernating female to hibernating female in a cave; they just sleep through it). 

But how does that work in terms of gestation? Brynne had pointed out that the bats are striving to save energy while they hibernate, so how does being pregnant impact the bat? And the answer apparently is, it doesn't, because bats practice -- Brynne called it "delayed implantation." A bat book I have on hand, meanwhile, actually on Australian bats, by Sue Churchill, connects this with the concept of "delayed ovulation". From Churchill's book:

Before an egg is released, it must develop in a small ovarian space called a follicle. In most mammals the follicle development cannot be stopped without the egg dying. However, bats can delay this succesfully: the process is called delayed ovulation and the signal to release the egg is not given until winter is over. Of course the sperms are now wandering around aimlessly and would die except that bats can store sperms in the female by plugging each sperm head in a tiny depression in the lining cells of the uterus where it is nourished and protected until spring when the egg is released and fertilisation occurs. [Note: this is apparently the preferred method among microbat species].

To avoid having to store sperms for the winter, the female body can permit the fertilisation and early development of the embryo to the stage wehre it can make primitive placental cells. The early embryo, calleda blastocyst, is held loose in the uterus in the process of delayed implantation [the blastocyst implants in the uterine lining, that is; I at first though Brynne had meant a wandering sperm implants in an egg]. When food resources are available again in spring, implantation takes place and the pregnancy resumes growth. 

Like, seriously, which of my readers knew any of that was biologically possible? I'd be the kid in class putting up my hand for question after question, here. Like, the bit about how "bats can store sperms in the female by plugging each sperm head in a tiny depression in the lining cells of the uterus": how is that, exactly, accomplished? Do the sperms somehow know which niches to plug their heads into? Do they have some sort of sensory organ to know where the niches are? Do they essentially also go into hibernation? What are the actual mechanisms at work here, and what are the advantages of doing it this way as opposed to, like most mammals, just getting it on in the spring? (Apparently something like 130 other species of animal practice a similar trick, including bears, armadillos, weasels, seals and kangaroos). 

There is suddenly much more I want to learn about bats. I may pick up a book on Canadian ones! I also want to share another microbat photo, because it's so cute:

Interestingly, too, note that (some) bats perform oral sex, too, apparently, so sex isn't all just a matter of sleeping females and busy males. 

How is there so much interesting stuff out there about bats that I didn't know? Did you realize that the world's smallest mammal (depending on how you measure them, of course) is in fact the bumblebee bat, AKA "Kitti's hog nosed bat?" David M. told me about those today, and I bet he didn't know anything about them before agreeing to do this concert, either. (He too had to look up the correct pronunciation of the word "chiroptera", he tells me.  

If you come to the show tomorrow, I promise there will be other things you don't know, like, for example, the new song David and I have co-authored, which was the thing that required us to learn how to pronounce "chiroptera". Also, even if you, like me, are a longtime NO FUN song, there is at least one NO FUN tune I would guess you have not heard in any variant. David explains,

I'll be doing "Close The Drapes" on Sunday. It's a Jimmy Hamelin song from 1976's Pretentious album, the last one we did before I got the 4-track and the first one on which Dan Vere played guitar on a bunch of songs. Jim wrote the song as a first-person complaint from Udo Kier's Count Dracula in "Blood For Dracula", as well as a tribute to The Count from "Sesame Street". As such, it is unique in the annals of popular music.

That won't be the only tribute to The Count tomorrow, I expect, either. 

No advance tickets, just come to LanaLou's at 2pm.