Coenobita brevimanus, often referred to as the Indonesian land hermit crab, is a terrestrial crustacean. While sometimes mistaken for the “Strawberry hermit crab” (Coenobita perlatus), this species has distinct features. Its adaptability to a terrestrial lifestyle contributes to its appeal as a pet.
Identifying Coenobita brevimanus
Distinguishing Coenobita brevimanus involves observing several physical characteristics. A prominent feature is its disproportionately large, bulbous left claw, which lacks distinct stitch marks and serves for defense and scavenging. Their eye stalks are long and thin, tipped with round, dark eyes. Body coloration ranges from dark brown to deep purplish hues, though variations, including pink, can occur. Adults can reach 6-8 inches (15-18 cm) in length, making them one of the larger land hermit crab species.
Natural Habitat and Wild Behavior
Coenobita brevimanus is widely distributed across the Indo-Pacific region, from Zanzibar to Tahiti. These crabs primarily inhabit inland areas, including coastal forests, rainforests, and arid scrublands, often found up to 1.5 km from the shoreline. They are highly terrestrial, being the most land-adapted species within the Coenobita genus, rarely venturing close to the beach.
These crabs are predominantly nocturnal, spending their days sheltered under logs, leaf litter, or within caves. At night, they become active, foraging as generalist scavengers and decomposers of terrestrial debris. They consume a varied diet, including decaying plant and animal matter, and have been observed preying on smaller hermit crab species. This species is also social, often found in groups and communicating through tapping sounds.
Essential Care for Coenobita brevimanus
Providing a suitable captive environment for Coenobita brevimanus requires attention to mimic their natural habitat. A minimum tank size of 30 gallons (approximately 120 liters) is recommended for smaller crabs, with larger enclosures, such as a 75-gallon aquarium, necessary for adults. The substrate should consist of playsand and coco fiber, maintained at a depth of at least 5-6 inches (12-15 cm), or ideally 10-12 inches (25-30 cm), to allow for burrowing and molting. The substrate needs to be consistently moist, holding its shape when squeezed without being waterlogged.
Maintaining appropriate temperature and humidity levels is important for their well-being. The optimal temperature range for Coenobita brevimanus is 80-90°F (26-32°C), as they can become lethargic at lower temperatures. Humidity levels should consistently be above 70%, ideally 80-90%, achieved through regular misting and a moist substrate. Heating mats placed on the side or above the tank can help regulate temperature, but never directly underneath, as this can harm burrowing crabs.
Two separate water sources are necessary: one bowl of dechlorinated fresh water and another containing dechlorinated saltwater mixed with marine-grade salt. Both dishes should be deep enough for the crabs to fully submerge, with an accessible way to climb out. Their diet should be diverse, including commercial hermit crab foods, fresh fruits, vegetables, and protein sources like cooked meat or insects. Calcium-rich foods are beneficial for exoskeleton health.
A continuous supply of appropriately sized empty gastropod shells is crucial for Coenobita brevimanus. These crabs switch shells as they grow or find a more suitable option. Round-opening shells, such as green, silvermouth, Mexican, tapestry, and jade turbos, are often preferred. Providing multiple shell options ensures they have choices for their growth and comfort.
Molting and Longevity
Molting is a natural process for Coenobita brevimanus to grow, involving shedding their old exoskeleton and developing a new, larger one. Signs of an impending molt include decreased activity, increased burrowing, or a cloudy appearance in their eyes. During this vulnerable period, the crab typically burrows underground for several weeks to months, depending on its size, to molt in a secure, undisturbed environment. It is important not to disturb a molting crab, as this can cause significant stress or even death.
After shedding, the new exoskeleton is soft and requires time to harden. The crab remains underground, often consuming its old exoskeleton to reabsorb calcium and other nutrients. Coenobita brevimanus can live for an impressive duration in ideal captive conditions, with reported lifespans ranging from 12 to 70 years, though 5-8 years is a more common range in captivity. This long lifespan underscores the commitment required for their care.