18 October 2006

Mmm…shit

snailsonpoop1

In his 1934 review of British land mollusks, Boycott discussed their diets and noted that the "partly digested vegetables of rabbit and sheep dung are much appreciated." So he probably would not have been surprised if he had observed with me these mollusks, a Deroceras reticulatum and a Ventridens ligera, feeding on a pile of what was most likely dog poop on a sidewalk late this afternoon.

The sidewalk where I came upon this spectacle was bordered by a forest on one side and a narrow grass strip on the other. The introduced D. reticulatum is quite common around here. They live in backyards of houses, fields and at the edges of forests, whereas the native V. ligera is primarily a forest dweller. In this instance, both species probably came out of the woods, but whether they chanced upon this particular food item while crossing the sidewalk or were attracted to it by its smell, I don't know and I don't intend to carry out experiments to find out.

snailsonpoop2

Interestingly, Chatfield, in her 1976 review of the diets of European snails and slugs, made no mention of them feeding on feces.

A previous post featured an A. subfuscus eating a dead earthworm.

REVISION made 19 October: The original post identified the slug as an Arion subfuscus. Subsequently, Tim Pearce e-mailed me his opinion that the pictured slug can't be an Arion, because its breathing pore is in the back half of the mantle (in Arion the pore would be in the front half of the mantle). He also suggested that it is probably a Deroceras reticulatum. He was correct. I hadn't paid attention to the location of the pore, but instead relied on the slug's color, which is a shade of brown common in A. subfuscus.


Boycott, A.E. 1934. Habitats of land mollusca in Britain. Journal of Ecology 22:1-38.
Chatfield, J.E., 1976. Studies on food and feeding in some European land molluscs. Journal of Conchology 29:5-20.

10 comments:

Megan Paustian said...

Yuck...but I guess it's a ready source of protein. I don't think I've ever seen slugs feeding on the plentiful deer feces in the woods, which may be because they're less nutritious.

Marcus said...

i'd like to see how 'ship dung' looks like....

Roger B. said...

Over here in the UK, encouraging slugs and snails is sometimes recommended as a way of clearing up dog faeces in urban parks.

Personally speaking, I'd prefer it if dog owners just cleaned up after their pets!

AYDIN ÖRSTAN said...

Holy ship! Thanks, Marcus, I've corrected it.

clare said...

Still chuckling over the title of this post. I have never seen a snail or slug in this er... environment.

Pamela said...

Great serendipity!! I just saw this phenomenon for the first time today--slugs, three of them, on what was probably coyote scat. I didn't note the pore--but colour like yours. This was probably close to their last hurrah--a warm wet day, soon to be followed by cold wet days, and worse.

Snail said...

I've seen introduced slugs feeding on dog poo here. Not sure if they're so fond of cat poo.

I've been wondering what sustains native snails on rock outcrops and talus slopes in central Australia. It's probably the leaf litter that accummulates in the cracks. But I'd like to think they get a bonus from rock wallaby shit.

AYDIN ÖRSTAN said...

Chatfield's study that I cited was based mostly on the analyses of feces of snails. It wouldn't, of course, be possible to determine from that type of an analysis if a snail had fed directly on some dead plants or on the feces of a herbivore.

Howver, like Megan, I've never seen any snails or slugs on the common scats of deer & other mammals in the woods around here.

Anonymous said...

I was cleaning up my dogs poop in the yard and discovered what I belive to be snails (no shell) in several of the pieces. The yard is usually on the wet side for a few days after a rainfall. I am now concerned that the snails were excreted by my dog. Is it possible that the snails crawled into the waste to feed and were not from my dog?

AYDIN ÖRSTAN said...

What you saw were probably slugs feeding on your dog's poop. If your dog had eaten the slugs, they wouldn't have survived the trip thru its digeative system alive & intact.