A post about a giant penis for Mother's Day? What am I thinking!

In my last post I wrote about a lovely day gardening with my younger daughter, Mrs. Squirrel of Boulder Creek, who is soon to become a mother herself. I promised to tell you more about the fate of a certain blossom, seen below right on the ground, in this photo, as we were leaving for our post-garden-day walk:

Yes, it's the Pacific banana slug (Ariolimax columbianus) , found in damp coastal forests from Alaska to Santa Cruz county, with scattered populations as far south as San Diego county. Here it's doing what it does best - consuming detritus found on the forest floor. You can see it opening its little mouth in this image:

And in the next - you can see its mouth is closed, chomping on the petal. You can also see its breathing hole or pneumostome (on the lower side in the picture), leading to its single lung. (Keep this image of the chomping mouth in mind as you read later in this post...)

Isn't that cool! It had totally eaten the blossom in a few minutes. From Wikipedia:
Banana slugs are detritivores, or decomposers. They process leaves, animal droppings, and dead plant material, and then recycle them into soil humus. They seem to have a fondness for mushrooms, and they spread seeds and spores when they eat, and excrete a nitrogen rich fertilizer. Thus they are an important aspect of the ecosystem.
And by the way, I also read that they do not generally eat your garden plants - leaving that to the non-native European Black Garden slugs.

No, banana slugs are good for the environment. But that's not all. Warning - adult content follows!

Banana slugs are hermaphrodites, and they have penises about as long as their body! You can find this well attested to on various pages such as the following:
Some folks think that there is only one [species], A. columbianus, throughout the range; others claim the presence of a second, A. dolichyphallus. A definitive answer will be a long time coming.

Dolichyphallus translates as "giant penis", and the slugs we know and love definitely live up to it. Banana slug penises have evolved to be almost as long as their bodies. When you consider that the average banana slug is 6 - 8 inches long, this endowment is impressive even by our standards. While having a big member to show off before mating may be a plus when trying to get the attention of that special slimer, there are drawbacks.

Since slugs are hermaphrodites, each partner's wiener must fit into the other's genital opening. This makes choosing a mate of equal size a must. Before actually getting down to it, both partners check out each other's equipment - no slug can ever be accused of rape, because both partners must present their plumbing before anything else happens. If either slug miscalculates, it may get its wanker stuck during actual copulation and be unable to pull out afterward. When this happens, the unstuck partner bites off the stuck one's slughood - scientists call this "apophallation", though "Bobbitization" may have more of a ring in popular circles.
The text above is from a 1995 article, Slimes of Passion, published in a Santa Cruz paper - which accounts for the dated "Bobbit" reference! But it is actually a decent article and you can learn more about slug slime and other interesting aspects of the sluggish existence there.

Sammy the Slug is also the mascot of U.C. Santa Cruz, where my older daughter attended college.

Originally adopted informally to show the Santa Cruz students' anti-competitive attitude towards college sports, I think spectators now yell "Go Slugs" with the same enthusiasm as any other team followers. I wonder how many of them know about their mascot's hidden assets - I certainly didn't when I began writing this post!

Well, er, Happy Mother's Day!


I think there are actually at least three species of Ariolimax here. Your first photo looks much more like Ariolimax dolichophallus (slender banana slug), at least based on the research I've read from Janet Leonard. They are fascinating creatures, and I love seeing them in the garden. They're not just good for the environment, but without them, our redwood forests might not be the same, as banana slugs refuse to eat redwood seedlings, but do help to keep competing plants away from them so they can grow! How cool is that? We did a post a while back on these fascinating creatures too:
I love their camouflage ;)
Country Mouse said…
Thanks, Claire - your post is very informative and doesn't mention - large parts! I can recommend others to click there for a more - rounded picture. I was truly just going to post the pictures I snapped of the slug eating the flower, and did 10 mins quick googling to add some background. - What I came up with was mostly the tawdry items of which my post is now one! I saw way more banana slugs in Boulder Creek than we see here - it being so much wetter and more deep in the redwoods than we are. It is interesting about the redwood symbiosis isn't it? I also read that they roll up in a ball and secrete a lot of slime when threatened, so predators can't deal with the nasty tasting big slimeball they present as! I didn't come up with your interesting info about three species - what I found on a cursory search said maybe but not certainly there are two species. If I opened a book instead of a laptop I might come up with more solid info!
You know, when I clicked on this on Blotanical I really thought the title was hilariously truncated and that once the page loaded I'd see the title was really something like "A post about a giant penisetum" or something. Banana slugs are sort of grossly aesthetic... like other things.
grumblebunny said…
it being so much wetter and more deep in the redwoods...

Country Mouse said…
Now now, grumblebunny, what are you thinking!
Town Mouse said…
Who would have thought? That is truly fascinating, and I had no idea. Really. This is not why I encouraged you to do a post about banana slugs. Regardless, they've always made me smile and now I'm smiling even more...
James said…
Oh lucky hermaphroditic slugs. They get to celebrate Mother's and Father's Days... My marine biologist cousin has stories about the organs of barnacles, which apparently put banana slugs to shame. I'm not up on sex among the submerged so I'm not sure if they're technically penises or not. But it does make for good college pub dinner conversation...
Well, it is quite fascinating and educational...so thanks for sharing;-)