
Thin-Shelled Rock Crab
grapsus tenuicrustatus
The Thin-Shelled Rock Crab, scientifically known as Grapsus tenuicrustatus, is a highly active and incredibly agile crustacean native to the rocky coastlines of the Indo-Pacific region. Commonly referred to as the Natal lightfoot crab, this species is famous for its astonishing speed and ability to leap across gaps in tidal rocks to evade incoming waves and hungry predators. It occupies the high intertidal zone, navigating the harsh, wave-swept splash zone with ease using its specialized gripping legs. As an ecological generalist, this crab plays a vital role in maintaining the health of coastal ecosystems. It grazes on algae covering the rocks and scavenges on organic debris, acting as both a cleanup crew and a critical link in the marine food web. Watching one of these crabs navigate the slippery, vertical faces of volcanic shorelines is a mesmerizing display of natural adaptation and athletic prowess.
Hábitat: Found on exposed, wave-beaten rocky shores, cliffs, and jetties in the intertidal and splash zones.
Aspecto
This medium-sized crab features a highly flattened, circular carapace measuring roughly 5 to 8 centimeters in width. Its coloration ranges from a dark, mottled olive green to brownish-black, often highlighted with fine pale yellow or white speckles that match the texture of wet basalt rocks. It possesses long, flattened legs equipped with sharp, needle-like tips at the dactyls, which allow it to secure a firm grip on slick rock surfaces, alongside short but powerful claws.

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AnimalRareza
Common
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Datos interesantes
Their flattened bodies are a specialized adaptation that minimizes drag from crashing ocean waves and allows them to squeeze into tight rock crevices.
This species is known as the lightfoot crab because it can run so fast that it appears to glide effortlessly across the surface of water and wet rocks.
To breathe while out of the water, they run water over their gills from a reservoir kept in their gill chambers, continuously aerating it.
Habilidades especiales
Agile Rock Leaping
This crab can leap or jump across wide gaps between wet coastal rocks to rapidly escape predators or heavy wave impacts.
Gripping Dactyls
Its legs terminate in sharp, spine-like tips that act like crampons, allowing the crab to cling securely to sheer vertical cliffs amidst crashing waves.
Sacrificial Autotomy
It can voluntarily drop its limbs when grabbed by a predator and later regenerate them during subsequent molting cycles.
Medidas y detalles
- Longitud
- 5-8 cm
- Peso
- 0.05-0.15 kg
- Esperanza de vida
- 2-4 años
- Top Speed
- 8 km/h
- Tamaño de la puesta
- 5000-20000
- Incubación
- 14-28 días
Dieta y alimentación
Primarily grazes on marine algae growing on intertidal rocks, but opportunistically scavenges animal matter and preys on small invertebrates.
Alimentos principales
- Filamentous algae
- Sea lettuce
- Marine detritus
- Small gastropods
- Carrion
Método de búsqueda
- Foraging And Grazing
Conexiones ecológicas
Day Octopus
Octopus cyanea
Preys upon the crab in tidepools and lower rocky shelves.
Yellow-edged Moray
Gymnothorax flavimarginatus
Hunts the crab when they venture too close to submerged rocky crevices.
Sea Lettuce
Ulva lactuca
Serves as a primary food source for the crab as it grazes on rock surfaces.
Rasgos
Aún no hay insignias de rasgos asignadas a este objeto.
También conocido como
Todavía no hay alias listados.
Colecciones
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Seguridad
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Preguntas frecuentes
¿Cómo identificar a Thin-Shelled Rock Crab?
La forma más fácil de identificar a Thin-Shelled Rock Crab es usar la aplicación de identificación de naturaleza Snappit.
¿Cuál es el longitud de Thin-Shelled Rock Crab?
5-8 cm
¿Cuál es el peso de Thin-Shelled Rock Crab?
0.05-0.15 kg
¿Cuál es el esperanza de vida de Thin-Shelled Rock Crab?
2-4 años
¿Cuál es el top Speed de Thin-Shelled Rock Crab?
8 km/h
¿Qué come Thin-Shelled Rock Crab?
Primarily grazes on marine algae growing on intertidal rocks, but opportunistically scavenges animal matter and preys on small invertebrates.
¿Dónde se encuentra normalmente Thin-Shelled Rock Crab?
Found on exposed, wave-beaten rocky shores, cliffs, and jetties in the intertidal and splash zones.
¿Cómo caza Thin-Shelled Rock Crab?
Foraging And Grazing
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