Hermit crabs are amazing creatures which can be both terrestrial or aquatic. They are often misunderstood as crabs, but they are not actually crabs. These crustaceans are the best friend of sea Anemones. Come, as this fact list will guide you to understand them better.
1. Hermit crabs are not crabs actually, they don’t have hard exoskeleton. They do have hard protective shell at the front but, the abdomen and tail section is soft. Rather they are mostly close relative to Lobsters.
2. These creatures grow 0.5-16 inches and can be of reddish, orange or brown colored with or without having purple spots on the body.
3. They have soft, asymmetrical abdomen, 10 legs and 2 large claws. The left claw is larger and serves as a weapon against predators such as cuttlefish, squid, octopus and different types of fish, whereas the right is used to collect food.
There are around 800 species of them including both terrestrial and aquatic. The aquatic crabs get their oxygen from water through gills whereas, the land crabs also breathe through their gills but need humid environment(at least with 70% humidity) to keep their gills moist.
Unlike other crabs, these species don’t grow their own shell. In fact, they seek others’ shell. They don’t steal but rather search for vacant shells. Different types of abandoned shells can be used, such as sea snails which can protect it’s soft body and provide moist environment for gills.
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6. Like other crustaceans, Hermit crabs molt as they grow. Their old exoskeleton get split and replaced by the new one. It take some time to harden so, they dig inside sand for protection. Also, they change their shell as they outgrow. Young crabs molt every few months, while adults molt once in every 18 months.
They are omnivores as well as scavengers. Their diet is based on fishes and sea invertebrates, fruits, vegetables, meat, leaves and anything leftover they can find.
8. They are nocturnal and require just little amount of light to see but, excess light could harm their eyes. So, they sleep during the daytime and hunt for food at night. If getting uncomfortable, they sever their eye sockets with their pincers.
Despite the name, they are not solitary creatures. They live in large colonies of 100 or more individuals.
All types of hermit crabs mate in the ocean. Females carry around 200 fertilized eggs attached to her abdomen until they hatch. Larvae emerge from the eggs usually after few weeks and float on the surface of the ocean during the first few days of their life. After several development stages they transform into juvenile crabs.
Hermit crabs and Sea Anemones do have symbiotic relationships. It is mutually beneficial. The Anemones share the food with crabs relying on the scavenging nature of the host, and in return the crabs get extra protection due to the venomous stings of the Anemones.
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12. They may not be very intelligent but, they do have good memories. They can remember scent or identify friend or foe. Also they can remember shells that have previously been occupied, painful experiences that should be avoided in future, what they have eaten recently, other crabs whether they are dominant or aggressive.
The Coconut crab is largest terrestrial invertebrate on the planet, and relative to Hermit crabs. These creatures can grow over 3 feet with massive pincers having force of approximately 750 pounds. Impressive yet dangerous to get too close.
14. Most hermit crabs do live for 5-15 years, but some live up-to 25 years. There have even been some lucky crabs that have lived in captivity for up to 40 years.