statolith

biology

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July 14, 2026

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A statolith is a small, dense body found within a statocyst, which is a sensory organ responsible for detecting gravity and maintaining equilibrium. These organs are present in many invertebrates, such as jellyfish, crustaceans, and mollusks, and analogous structures, the otolith organs, are found in the inner ear of vertebrates.123

Statoliths, often composed of calcareous material or starch grains, are suspended in a fluid-filled vesicle. As an animal changes its position, the statolith moves, stimulating sensory cells in the vesicle wall. This stimulation provides the animal with information about its orientation in space, allowing it to make compensatory movements to maintain balance. This mechanism is crucial for orientation and movement, especially when animals are not in contact with a solid surface.123

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crustacean
The nervous system
…or more small granules, called statoliths, that rest on numerous small setae. Any change in orientation causes the statoliths to impinge on the setae at a different angle, and this information is relayed to the brain so that corrective action can be taken. Finally, other setae are chemosensory; they detect…
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…or more small granules, called statoliths, that rest on numerous small setae. Any change in orientation causes the statoliths to impinge on the setae at a different angle, and this information is relayed to the brain so that corrective action can be taken. Finally, other setae are chemosensory; they detect…
Read More

mechanoreception
Gravity receptors
…sandy or stonelike elements (statoliths). Sensory cells in the wall of the vesicle have hairs that are in contact with the statolith, which always weighs vertically down. Hence, depending on the animal’s position, different sense cells will be stimulated in statocysts with loose statoliths, or the same sense cells…
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…sandy or stonelike elements (statoliths). Sensory cells in the wall of the vesicle have hairs that are in contact with the statolith, which always weighs vertically down. Hence, depending on the animal’s position, different sense cells will be stimulated in statocysts with loose statoliths, or the same sense cells…
Read More

proprioception
…more tiny, stonelike grains (statoliths). The statoliths may be free-moving, as in most mollusks, or loosely fixed to the sense hairs, as in some crustaceans. Statocysts are also found in many cnidarians and worms. Comparable organs in vertebrates are the saccule and utricle of the ear, the grains being…
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…more tiny, stonelike grains (statoliths). The statoliths may be free-moving, as in most mollusks, or loosely fixed to the sense hairs, as in some crustaceans. Statocysts are also found in many cnidarians and worms. Comparable organs in vertebrates are the saccule and utricle of the ear, the grains being…
Read More