The Explosive Shell
By Stella M. Turk MBE
Theba pisana is a xerophile
(it likes it dry)
Theba pisana is a calcophile
(it likes it ‘sweet’)
Theba pisana is a thermophile
(it likes it hot)
Theba pisana is a snail
With a very long trail.
For when its got all it could need
Plus plenty of plants on which to feed
Its populations start to explode
In many far-flung parts of the globe.
First in North Africa, later Australia
And for good measure California.
In Ireland, Wales and Cornwall - all Celtic lands -
It lives on the warm, dry, limeful shell sands.
If its too hot it aestivates
If too cold it hibernates
And in this dozy manner
It has spread from St Ives to Bude Bay
Watch out Devon - it’s coming your way!
The White (or Sandhill) snail (Theba pisana)
This attractive-looking snail is known for its ability to emigrate by water and land (probably in cargoes and on cars) and to reproduce in prodigious numbers in the right conditions. Colonies were known in Wales, Ireland and Cornwall (The Island, St Ives) at the end of the 18th century, remaining small and stable for a couple of centuries. Two decades ago, they started to appear in a series of ‘explosions’ at various points along the north coast of Cornwall, the focal points usually being car parks. Here they can occur in millions on the maritime vegetation.
Stella M Turk MBE
30th November 1998