The birds and the bees (or, at least, the ducks and the bedbugs)

Content warning: this article contains animal genitals. Lots and lots and lots of animal genitals. Also animal sex, animal rape, and other things related to animals “doing it”.

Let’s start with ducks. Here’s a link, if you want a picture (and a better explanation). Basically, male ducks have corkscrew-shaped equipment, with the length varying considerably by species. That’s weird enough. But female ducks often have equipment that corkscrews *in the other direction*, with blind pockets and so on. That’s because there’s this weird rape war going on with duck genitals.

Ducks often form monogamous pairs (at least, for the length of the mating season), but male ducks sometimes, well, want what they can’t have. So they will rape a female that isn’t willing to mate with them. The main defense female ducks have to avoid getting impregnated by their rapists is their, um, screwy vaginas. Basically, it’s very hard for a male duck to find the right place to deposit his sperm with an uncooperative female duck. Species of duck that do this a lot tend to have longer, more elaborate genitals (on both sexes), while less, well, rapey duck species tend to have smaller, simpler genitals.

Now on to the bedbugs. They are perhaps the epitome of a fun little trick known as traumatic insemination. That basically means that, instead of a male sticking his genitals into a female’s genitals, he just sort of… stabs her in the abdomen. Then the sperm wanders through her hemolymph (what insects have instead of blood) until it reaches her ovaries. Bedbugs do this often enough that they even have a special patch of tissue with extra immune cells for males to stab, so that the female (or other male–yes, bedbugs will penis-stab other males–scientists aren’t entirely sure why) doesn’t die from, you know, *being stabbed in the abdomen*.

Now let’s move on to snakes and lizards. They have hemipenes. That basically means that, instead of having a single tube to take sperm from their testes to their mate, they have two, with one tube coming from each testicle. They are kept inside the cloaca most of the time, usually only being everted (stuck out) when the male is attempting to mate. They have many different shapes (here are some pictures ).

Similarly, a lot of male marsupials, as well as platypuses, have two-headed penises ( marsupials here, platypus here), and echidnas have four heads on theirs ( here’s a picture and more details ). Reciprocally, most female marsupials have two vaginas and two uteri. And, just for a dose of cuteness to possibly counteract all of this a bit, the proper term for a baby echidna is a puggle. And they are as round and squishy-looking as you’d expect from their name. A few pictures.

Now let’s move on to primates. I’ll mainly discuss gorillas and bonobos. Despite their size, gorillas typically have a penis smaller than either a human or a chimpanzee–about as long as my pinky (3-6 cm, or about 1-2 inches–here are some details). This is mostly because of (female) monogamy. Since female gorillas generally only mate with one, dominant male, there is virtually no sperm competition going on. So, male gorillas only need, well, enough to get the job done.

Bonobos, on the other hand, are kind of notorious for, well, how much sex they have. Here’s an article on the topic. They have sex about like we shake hands or something–to greet each other, to bond, to make up after fights, to relieve stress, or just, well, because. They have sex in just about every possible combination (male/female, male/male, female/female, multiple partners, juveniles, et cetera, et cetera).

And a few more notable animal genitals or genital features:

Cats (and several other, mostly unrelated, species) have backward-facing barbs on their penises, known as penile spines. I’m glad I’m not a female cat.

A lot of different placental mammals have a baculum, or penis bone. Which means that, yes, their boners involve actual bone.

Female spotted hyenas have a pseudopenis, that is exceedingly similar to the actual penis that males have (some details here) And, yes, they both mate and give birth through them. Which does not sound fun in the slightest. And it leads to the death of both a fair fraction of the babies (especially a female’s first cubs, afaik) and a fair fraction of first-time mothers. Here’s an article with more information.

Relative to their size, many barnacles have the longest penises in the world, often up to 8 times the length of the rest of the barnacle.

Several animals, including elephants, whales, and tapirs have penises that are at least partly prehensile. (and here’s an article on dolphin genitals, female dolphins have some of the same tricks as female ducks to deal with rapists)

Several invertebrates, including honey bees, some octopi, some spiders, and some slugs actually detach their penis at some point during the process of mating, leaving it behind in their mate.

There are plenty more out there (I was trying to find a good picture of flatworm penis fencing, which is… pretty much what it sounds like), but my search history is probably weird enough as it is.