Monday, 8 August 2011

On the Technical Use of Gastropods (or how to stop a squeaky wheel)

I stood on a slug on Friday. Arion to carrion. You see, they closed the car park near my office so I now have to park right up the top of the hill.  This means that I start my day with a ten minute scenic detour along the track at the woodland edge. (Every cloud has a silver lining).  So it was this morning that I disturbed a roe deer and as it stepped out onto the track right in front of me, I stomped to an emergency stop and experienced that unmistakable oozy sensation of shoe upon very large slug. (Every silver lining has a cloud.).

I'll save you the gore of the squashed one - the Arion ater that I stood on looked like this before the close encounter with Doc Martin.
Arion ater, Mountjoy, Durham
Now here's a thing. In rural Sweden, in days of yore, their 4-wheeled carts had hard wood tree trunk axles, and used to squeak like hell and drive everyone crackers.  In no time some bright Swede realised that a couple of those big Arion slugs were just the job - simply squash them in the gap and hey-presto, silence.  You can almost hear the sighs of relief and the lowering of shoulders as the hapless molluscs do for the cart wheels what WD40 just did for my door hinge. 

Furthermore, immigrant German glass blowers in Sweden's southern parts collected Arions to smear on their frying pans when cooking pancakes, and in Essex, kids collected them along the railway lines to sell to the rail workers to lube their wheels (just the job when badger lard is in short supply).

If you think I'm making this up, read the whole paper, gloriously entitled, 'Black Slugs (Arion ater) as Grease: A Case Study of Technical Use of Gastropods in Pre-Industrial Sweden'here. Nice one Ingvar.

The colour variation in Arion is interesting.  There is a north-south divide. In Northumberland, I've only ever seen the jet black version. They are black in Sweden too.

Arion ater, Chillingham, Northumberland
In the south of England I read that most are red/orange/white ie anything but jet black. (Can my southern English readers confirm this?).  In Durham, there seems to be a bag of all-sorts as if we are on the overlap.

Brown ones of varying shades of light and dark.
Black ones with a snazzy orange and black skirt.
I had some interesting discussion with Phil Gates about this on his blog a while back.  Worth a look (here) if you missed it, if only for Phil's magnificent close up pictures which, as per, knock the spots off mine.

(Postscript - 27-08-11:  Have a look at Blackbird's excellent blog for an interesting post on species and colour variations. The link is here.   Looks like I will have to edit my post to read Arion sp. !)


  1. Hilarious post and cracking published paper you found!! Will go out on slug watch tonight and look for Arion aters. Few years ago I found a carnivorous slug in the garden (Testacella as I recall). Been meaning to turn some stones to see if there are some still up there. How odd though, I was telling some rugby fans on the train home the other night about carnivorous slugs (I am a fascinating train buddy). Mel

  2. I side-footed a fat pale brown (southern slug?) from our front path last night.

  3. Amazing! Why aren't more research papers as interesting as this one?

  4. Thanks Mel. I await your further report! Rob's on the Isle of Wight are pale brown so you can now take the Arion colour line further north a bit.

    Hi Phil: I guess there's only so many of this calibre that the world's academics can produce each year. This one is worthy of a nomination for an Ig-nobel prize in my opinion. Might just do that when I get back from my hols!