Yuletide cheer for all!! With that time of year approaching at more then a snail’s pace I wish all who read this seasons greeting. Last week the brutish Emui Moustache Toad showed off his spines in a bid for domination. This week we surf and sail towards the new year with this week’s creature. Hope you guys enjoy.
Issue #45 Plough Snail
Kingdom – Animalia
Phylum – Mollusca
Class – Gastropoda
[Clade]* – Neogastropoda
Family – Nassariidae
Genus – Bullia
* At the moment the Class Gastropoda is going through a taxanomic shake-up with no easily defined Orders. As such the Plough Snail could be in the following order; Caenogastropoda, Hypsogastropoda and Neogastropoda
Related Species - There are a wide range of scavenging shoreline snail in the family in the genus Bullia (1)
Range - The Plough Snail can be found along the southern shoreline of South Africa
Masters of the Surf
The Plough Snail has a single shell, of around 60mm long, with five whorls that spiral towards a single point. The shell is usually cream but there are colour variations ranging from yellow to purple. The foot of the snail is a thick white and spreads around the entire shell. When threatened the snail retracts its foot into the shell and closes the operculum, the calcareous trapdoor that protects the snail’s soft parts, and relies on the serrated edge to passively deter predators from trying to break open the shell (2).
The Plough Snail feeds on carrion washed up on the beach at high tide but faces the problem of desiccation from the sun and predation from sea birds. To reach the food the Plough Snail extends its foot and lets the tide push the snail up the beach. As the tide retreats the snail buries itself in the mud to prevent being washed away by the waves. As soon as the water level drops the snail re-emerges and heads up the beach to the high tide mark. While the snail is unfussy on what they feed on they do have a preference for stranded Portuguese Man o War (Physalia physalis) with hundreds of Plough Snails converging on a single washed up colony (3).
As the tide comes back in the snails move back towards the ocean, leaving a distinct furrow behind them before burrowing back into the sand to re-hydrate itself. Like the majority of marine gastropods the Plough Snail has distinct genders with the females laying a solid mass of eggs below the low tide mark.
Five Fun Plough Snail Facts
Be careful when picking up a Plough Snail, the species doesn’t distinguish between living and dead flesh and has a nasty bite (I know from past experience)
Plough Snails are so successful that on some beaches they have out competed other coastal invertebrate scavengers (4)
Plough Snails feed by liquefying flesh and sucking it down a proboscis towards the radula
Distant relations the Moon Snails have taken their role as coastal scavengers to a new level. One species uses its foot to smother still living prey before drilling into the carapace and liquefying its insides.
Plough Snail shells make the perfect home for Hermit Crabs
1 - www.arkive.org
2 - Antonio G. Checa and Antonio P. Jiménez-Jiménez, Constructional Morphology, Origin, and Evolution of the Gastropod Operculum; Paleobiology, Vol. 24, No. 1, Winter, 1998
3 - Matthews, L. (2007). The coastal guide of South Africa. Coastal guide. Johannesburg: Jacana Media. p. 131
4 - BRANCH, G.M., GRIFFITHS, C.L., BRANCH, M.L. & BECKLEY, L.E. (2002). Two Oceans: A Guide to the Marine Life of Southern Africa. Cape Town & Johannesburg: David Philip Publishers. p. 360
1 - http://upload.wikimedia.org/wikipedia/commons/4/4d/Bullia_digitalis_-_Plough_snail_0347.jpg
2 - http://upload.wikimedia.org/wikipedia/commons/f/f8/Bullia_digitalis_-_Plough_snail_003.jpg
3 - http://cache2.asset-cache.net/gc/116781568-plough-snails-eating-a-blue-bottle-cove-rock-gettyimages.jpg?v=1&c=IWSAsset&k=2&d=zNbeuEd5xDvVwiMX%2FmAuaPxZuP3OHRWY721hCUR5QWs%3D
And as the tide comes in the Plough Snail surfs into 2015 alongside Impurest’s Guide to Animals . Next issue features the much requested Pistol Shrimp who starts the new year off with a bang, but until then critic, comment and check out Impurest’s Bestiary of Past Issues