Knobbed Whelk
ExploreInvertebrate
Knobbed Whelk
busycon carica
The Knobbed Whelk (Busycon carica) is a spectacular and robust marine gastropod native to the shallow coastal waters of the North Atlantic. Known as a heavy, slow-moving predator, this sea snail plays an essential role in keeping local bivalve populations balanced. The species has historically been highly valued, notably used by Native Americans to craft wampum beads, and is currently honored as the official state shell of both New Jersey and Georgia. It serves as a fascinating example of marine adaptation along the eastern seaboard of North America.
Habitat: Found in shallow coastal waters, estuaries, and sandy or muddy intertidal flats along the Atlantic coast.
Appearance
The heavy shell of the Knobbed Whelk is distinctly dextral, meaning the opening or aperture is situated on the right side when the spire points upward. It features a sequence of prominent, low spines or knobs along the shoulder of each whorl. The shell's exterior displays a dusty, light-gray or tan coloring that camouflages it against sandy bottoms, whereas the interior aperture is famously flushed with a vibrant, warm orange-yellow hue. Adults usually measure between 12 and 30 centimeters in length and taper into a long siphonal canal.
KingdomAnimaliaPhylumMolluscaClassGastropodaOrderNeogastropodaFamilyBusyconidaeGenusBusycon
Category
InvertebrateRarity
Common
Danger
1/5 · Very low
Snaps
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Interesting facts
Native Americans used the strong central columella of the knobbed whelk shell to carve white wampum beads used for currency and trade.
The Knobbed Whelk is the official state shell of both Georgia (since 1987) and New Jersey (since 1995).
They lay their eggs in a long, papery, spiral chain of capsules often referred to as a 'mermaid's necklace' which frequently washes ashore.
Whelks are 'right-handed' (dextral) snails, unlike the closely related Lightning Whelk, which is 'left-handed' (sinistral).
Special abilities
Ability
Shell-Prying Leverage
The whelk utilizes the hard edge of its own shell as a wedge to chip and pry open the tightly closed valves of clams and oysters.
Ability
Chemosensory Hunting
It uses a highly specialized olfactory organ called an osphradium to detect prey chemicals carried by the water current.
Ability
Radular Drilling
Once a prey's shell is slightly parted, the whelk inserts its rasplike radula to scrape and consume the soft tissues inside.
Measurements & details
- Length
- 12-30 cm
- Weight
- 0.2-1.5 kg
- Lifespan
- 10-20 years
- Clutch Size
- 40-150
- Incubation
- 90-120 days
Diet & Feeding
A specialized carnivore feeding mainly on bivalves by utilizing mechanical leverage to break or wedge open their shells.
Age differences: Juveniles feed on smaller bivalves or carrion before transitioning to large clams and oysters as adults.
Primary Foods
- Hard Clam
- Eastern Oyster
- Blue Mussel
Foraging Method
- Foraging
Ecological connections
hunts
Hard Clam
Mercenaria mercenaria
Predates upon hard clams by using its shell lip to pry their valves apart.
eaten by
Forbes' Sea Star
Asterias forbesi
Preys upon young and mid-sized knobbed whelks.
eaten by
Atlantic Rock Crab
Cancer irroratus
Juveniles are vulnerable to predation by larger coastal crabs.
Traits
No trait badges are assigned for this object yet.
Also known as
No aliases listed yet.
Collections
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Safety
Danger
1/5 · Very low
No special safety notes yet.
Frequently Asked Questions
How to identify Knobbed Whelk?
The easiest way to identify Knobbed Whelk is to use the Snappit nature identifier app.
How long is Knobbed Whelk?
12-30 cm
How much does Knobbed Whelk weigh?
0.2-1.5 kg
How long does Knobbed Whelk live?
10-20 years
What does Knobbed Whelk eat?
A specialized carnivore feeding mainly on bivalves by utilizing mechanical leverage to break or wedge open their shells.
Where is Knobbed Whelk usually found?
Found in shallow coastal waters, estuaries, and sandy or muddy intertidal flats along the Atlantic coast.
How does Knobbed Whelk hunt?
Foraging
How many eggs does Knobbed Whelk lay?
40-150
Snap Map
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Recent Snaps
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Where to spot
Park30 sightings12 species
US
Cape Lookout Coast Guard Station
You might spot Firewheel, Domestic Horse, and Atlantic Horseshoe Crab.
View guide →
Park30 sightings12 species
North Carolina, US
Cape Lookout Village Historic District
You might spot Firewheel, Domestic Horse, and Atlantic Horseshoe Crab.
View guide →
Park30 sightings12 species
Delaware, US
Fort Miles
You might spot Atlantic Horseshoe Crab and Atlantic Ghost Crab.
View guide →
Park30 sightings12 species
New York, US
Orient Historic District
You might spot Eastern Box Turtle, Osprey, and Low Pricklypear.
View guide →
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