When you think about crabs, it’s not uncommon that crabs on a coastline or in freshwater ecosystems come to mind.
But did you know there’s a species of crab that spends most of its time in the forest?
Aquatic ecologist Dr Ryan Mohammed told Newsday Kids the Caribbean soldier crab (
Coenobita clypeatus) is one of only a few species of hermit crabs adapted to spending long periods on land.
He explained, “Because they have a terrestrial component in their life cycle, they are able to venture far into the forest. It is very unique to see them going all the way into the forest.
“This species has adapted to a terrestrial lifestyle to capitalise on land-based food resources.”
While they spend a lot of time on land, these crabs do journey to the sea ever so often.
Like all hermit crabs, Caribbean soldier crabs salvage and occupy the shells of other organisms.
So, throughout their lifetime, these crabs search the coastline for loose shells to call their own when needed.
For this reason, Mohammed is discouraging people from taking abandoned shells from beaches as they may be denying these crabs a suitable home.
“They rely on gastropod shells, mollusc shells, and snail shells, for that extra protection of their soft outer bodies.”
He added, “Like all decapod crustaceans, they also still need to come down to the edge of the water to reproduce and complete essential stages of their life cycle.”
If you never see these crabs in the forest, there’s a chance you may hear them as they vibrate the appendages within their shells which makes a screeching sound.
“Walking through the forest, you can actually hear this sound if you listen well.
“They do form aggregations in the forest which is why they are sometimes easy to collect. When you find one crab, you’ll eventually find a lot.
“They form these daytime aggregations in the forest vegetation when they are trying to get away from elevated temperatures and direct sunlight.”
As omnivores, these crabs feed on food of both plant and animal origin but they are also scavengers which means they feed on corpses (bodies of dead animals).
As a result of this, these crabs serve a vital ecological function in that they break down the corpses and ensure their nutrients are recycled.
“In some islands, these crabs perform a major ecosystem function. Because they move nutrients from one form to the next, they provide that ecosystem stability.
“That, in turn, supports other populations like seabirds when they are near the sea and some of the forest-dwelling organisms when they are in the forest.
“They also help in the dispersal of many plants because they pick up the seeds when they eat and move them around.”
Found in a wide range of colours, Mohammed said this is one reason why people often want to keep these crabs as pets.
But even though they are sold in pet shops, that doesn’t mean you should buy them as Mohammed is warning people, they require a lot of care.
“They do have some very vibrant colouration on their claws which is why they are in the ornamental pet trade.
“Several people collect hermit crabs, sell to pet shops and then the pet shops sell them to people that find hermit crabs cute.
“But to care for these crabs can often become difficult. You have to make sure and maintain the right humidity and diet.
“One of these crabs can also live until ten years old, so unless you’re prepared to take care of an animal that long and provide what it needs...you are going to kill it within a few months.”