Geoduck
A geoduck is a large burrowing marine clam with a comparatively small shell and a very long siphon.
Also known as: Pacific geoduck, Panopea generosa
How big is it?
17 cm · defined shell length
Also 6.693 in
Defined shell length · defined specimen
Typical recorded range: 12 cm to 22 cm.
A little perspective
Geoduck vs Vanguard 1: length comparison
The shell length of a geoduck is about 1.03 times the satellite body diameter of Vanguard 1.
A geoduck is a large burrowing marine clam with a comparatively small shell and a very long siphon.
Vanguard 1 is an early American satellite launched in 1958, notable for being the oldest human-made object still in orbit.
Both rulers start at the same zero and share one linear scale. Artwork keeps its original proportions.
Measurements, assumptions & sources +
Geoduck
Defined shell length: 17 cm; defined specimen; range 12 cm–22 cm.
A defined Pacific geoduck with a 17 cm shell and 1.2 kg live mass. The long siphon can extend far beyond the shell and is shown for identity, but shell length is the calibrated span.
Washington Department of Fish and Wildlife — Geoduck
The marked defined shell length is calibrated. Unmeasured illustration details are representative.
Vanguard 1
Satellite body diameter: 16.5 cm; specified.
Vanguard 1 is a 16.5 cm diameter aluminium sphere with a launch mass of 1.474 kg. Its six antenna rods extend beyond the calibrated spherical body diameter.
The marked satellite body diameter is calibrated. Unmeasured illustration details are representative.
Use the visual comparison to explore its scale, then check the measurements and sources.
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Why this measurement?
Why we use 17 cm
We compare the shell length of a geoduck. This is an illustrative comparison value, not a claim that every example is the same. The recorded range is 12 cm to 22 cm.
A defined Pacific geoduck with a 17 cm shell and 1.2 kg live mass. The long siphon can extend far beyond the shell and is shown for identity, but shell length is the calibrated span.
The marked horizontal span follows the measured feature, not the edges of the image. How calibrated comparisons work →
Recorded properties
Dimensions and measurements
| Property | Selected value | Recorded range | Basis |
|---|---|---|---|
| 17 cm | 12 cm to 22 cm | defined specimen | |
| 1.2 kg | 700 g to 2 kg | defined specimen |
Around this scale
Explore nearby values.
Compare examples with lower, similar and higher values. Each card names the measurement being compared.
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Around the same scalePlanets, moons and spaceVanguard 116.5 cmSatellite body diameterVanguard 1 is an early American satellite launched in 1958, notable for being the oldest human-made object still in orbit.
Nearest higher valueLiving thingsQueen conch25 cmDefined shell lengthThe queen conch is a marine mollusc native to the Caribbean and western Atlantic, recognised for its spiral pink shell.Sources and method
Want to check the number?
The source records and measurement method remain available for inspection.
- Washington Department of Fish and Wildlife — GeoduckPacific geoduck shell, siphon anatomy and broad adult size variation; the atlas defines one specimen.
There’s always another scale
Follow your curiosity.
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