My recent recent excursion into the world of the earwig led, predictably, to the barnacle, because that is the nature of rabbit holes. Just as rabbit holes, themselves, famously lead to more rabbits, the pursuit of information in a medium with hyperlinks can lead to barnacles, if you’re doing it right. If you’re not doing it right, it could lead to conspiracy theories, but we’re trying to stay in the happy zone here.

An amazing amount of science has been perpetrated on the earwig, mostly by one fellow in Tokyo. Hey. It’s hard to find fresh thesis subjects these days. Among other things, Yoshitaka Kamimura removed female earwig reproductive organs and mounted them on a slide. It’s not as much fun as mounting them on a swing set, but you still have to give the guy credit.

The revelation that earwig males have two penises, in parallel, and that they’re as long as their own bodies, generated more questions. What animal has the largest penis? No real surprise there—it’s the blue whale, the largest animal that ever lived. The blue whale penis is at least twelve inches. That’s thickness. And it’s almost ten feet long. That’s one Moby…never mind.

You want something that sizable though if you’re a whale because whales are kind of round all over and you need to get a good purchase. They do it missionary style, but in the water it’s sort of irrelevant who’s on top. The penis is retracted into an S-shape inside the body when not called to attention. The testes are inside too, which presents an evolutionary challenge. Males of most mammal species have scrotums, the purpose of which is to keep the testes banging around outside the body so the sperms don’t cook, but such a structure would make no sense in the ocean, which is too cold almost everywhere. Plus it would ruin their line. Whales want to be streamlined. So they keep their sperms ready to roar by redirecting cooled blood from the fins and flukes toward their balls.

If you were still looking for an untapped biology thesis, you could do worse than boning up on blue whale penises. Evidently we’re still just guessing about it, because whales don’t want you to watch, or they’d be on dry land somewhere. We don’t even know exactly how they get an erection, although it probably does not involve blood, or porn.

But what animal has the largest penis in relation to its body size? It’s not the fabled earwig. No, it’s the barnacle that has a penis eight times its own length. This is the sort of thing that can develop when your life strategy is to glue yourself somewhere and your various beloveds are glued someplace else. Mating season among barnacles is a jolly affair, all waving penises looking for a good time. If I’ve witnessed it, I didn’t know it. I was quite taken with barnacles as a child, watching what looked like little egg beaters coming out of their slits, trying to net dinner as water passes over them. My early affection for the barnacle arose from my twin virtues of smallness and extreme myopia. Now that I’m not as bendable and have had my vision corrected, I’m more into birds.

All barnacles have penises to wave around, and once they’re done with them, they resorb them and grow a fresh one next season. Since humans have evolved to invent the remote control, many males of the species are now welded to the couch. But they haven’t needed to develop any remarkable phallic properties, because no one really wants to mate with them.