Olive shells are predatory snails related to whelks, mud snails, and tritons. There are 3 species represented on the west coast, but only Callianax biplicata
is found commonly on B.C. beaches intertidally; the others are less common and tend, anyway, to live more subtidally. Olive shells C. biplicata
are generally buried in the sand when the tide is out. They are nocturnally active, emerging from buried positions at dusk to search for small invertebrates to eat, or dead animal matter to scavenge. Predators include sea stars, crabs, shore birds, fishes, octopuses, and moon snails Polinices
. Effects of the last are most visually obvious to a beach-walker, as shells with characteristic counter-sunk drill-holes bearing testimony to moon-snail predation are often found in abundance. Defenses of olive shells include fast crawling, burial and, sometimes, swimming. For more on predators and defenses of Callianax
go to A SNAIL'S ODYSSEY
Note Author: Tom Carefoot, Department of Zoology, University of British Columbia.