1. Habitat: Land hermit crabs, as their name suggests, are terrestrial and primarily live on land. They are found in moist forest environments, coastal areas, and even arid regions. Marine hermit crabs, on the other hand, inhabit the ocean and are found in intertidal zones, shallow waters, and coral reefs.
2. Gills versus Lungs: Land hermit crabs have adapted lungs that allow them to breathe atmospheric oxygen. They have two small lung chambers located in their modified gill chambers. In contrast, marine hermit crabs have gills, similar to other marine crustaceans, which enable them to extract oxygen directly from seawater.
3. Appearance and Adaptations: Land hermit crabs tend to have a flatter, wider body structure, which helps them crawl more efficiently on land. Their legs are often shorter and more robust compared to marine hermit crabs. They also have sturdier claws that aid in climbing and gripping. Marine hermit crabs, on the other hand, have streamlined bodies, longer and more slender legs for swimming, and their claws are often adapted for grasping and feeding.
4. Food and Diet: Land hermit crabs are omnivorous and feed on a variety of plant matter, fruits, and organic materials. They can also scavenge on dead animals and other food sources found on land. In contrast, marine hermit crabs are primarily scavengers and feed on algae, small invertebrates, and other organic matter they find in the ocean. Some marine hermit crab species may also filter-feed on plankton and suspended particles in the water.
5. Molting Behavior: Land hermit crabs tend to molt (shed their exoskeleton) on land, often burying themselves in the substrate during this process. Marine hermit crabs, on the other hand, usually molt underwater and seek shelter among rocks or crevices in coral reefs to protect their soft, vulnerable exoskeletons during this phase.
By observing these key characteristics and behaviors, you can generally identify whether a hermit crab is a land or marine species.