Invertebrates
Dog Whelk
Nucella lapillus
On a barnacle-covered rock at low tide, a dog whelk sits over a mussel, its rasping tongue slowly drilling a neat round hole through the shell.
Overview
The dog whelk, Nucella lapillus, is a Not Evaluated sea snail of rocky shores in the northeast Atlantic. Its drilling hunting method, variable shell colours, and sensitivity to antifouling pollution make it one of the best-known predators of the rocky shore.
A snail that showed the cost of paint
When the antifouling chemical TBT leached from ship hulls, dog whelk females developed male characteristics and stopped breeding, one of the first clear examples of an animal harmed by a hormone-disrupting pollutant.
Status
Not Evaluated globally, and recovering since TBT was banned.
Dog Whelk: common questions
How does a dog whelk eat a mussel?
It bores a small hole through the shell using its rasping tongue and an acid secretion, then feeds through the hole.
What did TBT do to dog whelks?
The antifouling chemical caused females to develop male characteristics and stopped them breeding, so many populations crashed.
Why do dog whelks come in different colours?
Their shell colour depends partly on what they eat, so they can be white, yellow, orange, or banded brown.
Where is the dog whelk found?
It lives on rocky shores of the northeast Atlantic, from Norway and Iceland south to Portugal, and on the northwest Atlantic coast.