Dog Whelk (also known as the Atlantic Dogwinkle or Dogwhelk)
Phylum: Mollusca; Class: Gastropoda; Order: Neogastropoda; Family: Muricidae; Genus: Nucella; Species: Nucella lapillus · Muricidae (Murex or Rock Snail family) · Gastropod (univalve); Spiral/Fusiform whole shell
Species
Nucella lapillus (Confidence: 90%)
Shell Type
Gastropod (univalve); Spiral/Fusiform whole shell
Family
Muricidae (Murex or Rock Snail family)
Size
Approximately 25-35mm (1-1.4 inches). This is a standard adult size for the species, which typically reaches up to 60mm in ideal conditions.
Color & Pattern
Uniform creamy white to pale yellow. The specimen appears somewhat sun-bleached or naturally light-colored. In life, these shells can range from white and yellow to dark brown or banded with purple-black.
Rarity
Very Common. This is one of the most ubiquitous predatory snails found on North Atlantic rocky beaches.
Habitat
Intertidal zone, primarily on rocky shores. They are extremely hardy and can withstand significant wave action by clinging to rocks.
Geographic Range
North Atlantic coasts; found from the Arctic to Portugal in the East and from Canada to New York in the West.
Description
A robust, thick-walled shell with an oval to fusiform shape. It features a short spire and a large body whorl. The surface is sculpted with spiral ridges or 'cords.' The aperture is oval with a slightly thickened outer lip and a short, notched siphonal canal.
Key Features
Thick shell walls, diagnostic spiral cording, a short siphonal canal, and an oval aperture. Its shape varies significantly based on environmental exposure (flatter in high-wave areas).
Collector Value
Minimal financial value ($1-$5) due to its abundance, but high educational value for demonstrating morphological variation. Highly sought after when found in rare 'banded' color forms.
Condition Notes
Good condition. The shell appears intact with no visible major fractures, though the 'weathered' look suggests it was collected as a beach-worn specimen rather than taken live. Collectibility Grade: Fine.
Interesting Facts
The Dog Whelk is a famous example of 'ecophenotypic plasticity,' meaning its shell shape changes based on whether it lives on a wave-battered cliff or a sheltered bay. They prey on barnacles and mussels by drilling holes through their shells using a radula and acidic secretions.
Ecological Role
Key keystone predator in the intertidal rocky shore ecosystem. They help control the population of mussels and barnacles, preventing any one species from dominating the rock surface.
Similar Species
Urosalpinx cinerea (Atlantic Oyster Drill) which is generally more elongated with stronger vertical ribs; Littorina littorea (Common Periwinkle) which lacks the siphonal canal notch.
Beach Finding Tips
Check rocky tide pools at low tide. They are often found huddled in crevices or near colonies of barnacles and mussels, which are their primary food source.