After last week's post on whether the bears can smell the menstruation (hehe, I can't get over that quote), I was inundated with questions and tips for papers. People asked if menstruation attracted sharks (answer: no one has tested it, right now shark attacks are 9.2:1 male:female, but that's probably due to differences in being in the right place at the right time, rather than being on your period. But I think I need to dangle some bloody tampons in shark infested waters...for science), if dogs were attracted to the smell of menstruation (I've been looking and looking for studies, but apparently that hasn't been done either), all sorts of things. But the vast majority of these studies...haven't been done. From all the stories I've heard of animals being attracted to menstrual blood, you'd have thought every female Homo sapiens on the planet would be ripped apart by wolves the instant she started menstruating.
But we're all still HERE. So I have to think that, until there are studies proving otherwise, most other mammals, and hopefully sharks, don't really care if you're seeping a little bit of endometrium from your nether regions.
But there IS one species, apparently that DOES care.
The brown tree snake.
Chiszar et al. "Response of brown tree snakes (Boiga irregularis) to human blood" Journal of Chemical Ecology, 1993.
The brown tree snake is native to the South Pacific, but is apparently a major pest in Guam, where it was introduced accidentally after World War II. It's nocturnal, lives generally in trees, has a wide variety of teeth (two of which inject venom, but the venom is not dangerous to adult humans), eats almost anything, and is generally between three and six feet long. In Guam it's been a major problem for causing power outages, apparently by weighing down powerlines.
From the descriptions of the brown tree snake, I'm now getting the terrifying idea of a bigass snake that will cut the power, sneak up on you through the trees, and DROP ON YOUR HEAD FROM ABOVE AND ENVENOM YOU TO DEATH. Though apparently it's not that bad, just annoying (at least in Guam, where they use dogs to keep it from spreading to other islands and try to keep it away from people's pets and small children).
But there is this threat...ladies, this snake likes your menstrual blood.
So apparently the idea for this experiment came from Brown tree snake attacks on babies in Guam. The authors inferred that the snakes were attempting to eat the babies (mmmm, delicious babies), and wanted to know why. They hypothesized that, since snakes are attracted to the smell of blood, the snakes were finding the babies because they were smelled the discarded feminine products of the mothers which were in the trash. Because apparently all of these babies had menstruating mothers who kept their used tampons in the trash in the baby's room? I'm a little skeptical of the logic of this train of thought, but that's how they told it.
So in order to test this hypothesis, the authors took 10 captive snakes. They presented the snakes with used or unused tampons (moistened with water), and watched to see what the snakes did. They measured how often the snakes flicked their tongues at the tampons (evidence that they were chemosensing), and advanced toward the tampons. However, the snakes were not allowed to STRIKE at the tampons (though apparently they had this problem anyway) due to inability to retrieve said tampon from a very ornery snake.
And then they got their results. The pictures are, predictably, kind of awesome.
I happen to loathe when people put all their data in tables, so I'm going to graph this for you.
It's pretty obvious that them snakes really like some menstrual blood!
The authors concluded that human blood (in this case menstrual blood) attracts brown tree snakes. But we don't know if it's human blood, or menstrual blood specifically. In order to prove that, we'd need more tampons, this time with regular blood (apparently none of the authors were willing to make that particular sacrifice for this paper).
They also talked about not leaving your post-partum blood and menstrual blood around your baby, as it might be unduly attractive to snakes. I'm not so sure about this. I mean, even IF the bloody items were in the same room as the baby, I'm sure the snake could tell which was which. Snakes not only have chemosensing, they can sense HEAT. So if forced to choose between the cold bloody tampon in the trash and the warm delicious baby...well let's just say I don't think the snake cares about the tampon in comparison. You'd have to have bloody items right up ON the baby to really say it was making a difference. Brown tree snakes eat small mammals all the time, I think it's not too much to assume that a baby on its own is plenty attractive to them regardless of whether or not there's blood around (mmmm, delicious babies).
But the moral of the story is that, if there's any animal out there that likes your used tampons, it's the brown tree snake. Oh well, at least it's not bears.
Chiszar, D., Dunn, T., & Smith, H. (1993). Response of brown tree snakes (Boiga irregularis) to human blood Journal of Chemical Ecology, 19 (1), 91-96 DOI: 10.1007/BF00987474