What is a Hemipenis?
Hemi /ˈhemē/
- Half.
Penis /ˈpēnis/
- the male genital organ of most vertebrates, which helps with the transfer of sperm during copulation.
Why would I write a blog post about another animals penis? I am so down with highlighting differing sexual norms which exist outside of normative considerations within the dominant heterocentric colonial culture. Looking at other ways that animals get down is pretty revealing and helps us remember that there really is no “one right way” that is more natural or good. Life finds many ways to express. And, it’s pretty interesting.
The Hemipenes is the name of Eastern Garter Snakes (Thamnophis sirtalis sirtalis) penis’, and if we are only referring to one half of the whole structure, we can use the term hemipenis. A singular hemipenis is used at a time while mating. The reproductive organs on either side of the male’s body are entirely separate, unlike many other asymmetric structures such as lungs. That is, sperm produced in the right testis can exit the body only via the right hemipenis! Amazing.
As I watched the Garters writhing in their mating balls the other day, I wondered if there was a chance we would see the males hemipenis in action, but I didn’t make it out.
I have also learned that researchers have noticed that male Garters will sometimes alternate which hemipenis they use when copulating if the male gets multiple chances to mate. To clarify, if a male Garter ejaculates the sperm from his right hemipenis, he will then use the left hemipenis the next time he is mating. Some researchers used to think that it was because it took time for the sperm to be newly created, but for Garters, sperm production is done months before copulation. Instead, it is hypothesized that males are also releasing some sort of fluid from the kidneys as well as the sperm when they ejaculate. Researchers have also noticed that the size of the “mating plug”, a gelatinous material formed from secretions of the kidney immediately after insemination which plugs up or glues together the female genital tract which is supposedly deposited to prevent other snakes from mating with the female, which snakes often leave behind will be reduced in size if the snake is forced to use the same hemipenis repeatedly. Who are these researchers? How did they get this gig? Who funds it?
Another cool thing I found out about was the Hemiclitoris found on females of many different squamate (snakes and lizards) species. Researchers don’t know if the hemiclitoris organs serve a pleasure-based function, but it would be nice to think that female squamate reptiles are having double the fun other animals with only one solid clitoris have while getting it on.
Another cool penis I have been learning about is the forked penis that has one main shaft that splits into two at the end (if you want to see one, there is an photo I took recently at the bottom of this page). I first heard about this a while ago when I interviewed Doug Elliot, and listened to a story he had told about Virginia Opossums (Didelphis virginiana) at a story telling festival. To summarize, someone back in the day once thought that the male Opossum would insert his hemipenis into the female Opossum’s two nostrils, and ejaculate therein. A few days later folks would see the female Opossum putting her nose into her pouch. When later inspected, tiny baby Opossums were in the pouch attached at the teats, supposedly having emerged from the nostrils of the mother. Researchers believe that this method of reproduction is not accurate and have described an alternate method involving three vagina, two of which receive the sperm and are placed on the side, and a central placed median vagina which serves the purpose of a birth canal.The females also have two wombs which explains the Greek scientific name di: two, separate + delphys: womb.
Again, the image of the bifurcated penis of the Opossum is way below. Look if you want to, but a friend described it as “sooo gross!”
More info:
Are snakes right-handed ? Asymmetry in hemipenis size and usage in gartersnakes
Opossum hemipenis.