Hermit Crab Motel

Shell Cooperation Hermit crabs need shells to survive, but constantly outgrow them.  When it's time to trade up, hermit crabs will often line up in size order, swapping shells so each crab gets one that better fits them. – discovermagazine.com

You read it first in this week’s The Factory in Guide magazine.

Hermit Crabs are quite interesting characters. Have you ever seen their eyes? The compound eyes are actually on stocks and can turn 360 degrees to watch for predators. I don't know how scientists know this, but apparently the crabs can tell the difference between colors and shades, but not shapes.

They are crustaceans and arthropods. This means that they live mostly in water and have a hard shell, a segmented body, and jointed appendages. They are invertebrates and have exoskeletons. Exoskeletons are a hard outer shell covering the body to protect it and provide support.

But the hermit crab, unlike other crabs, have only a partial exoskeleton and they don't grow the shell they wear. That's why they like to live in discarded shells of other crabs. But they have an interesting problem. They outgrow their borrowed shells fairly often and have to give them up to look for larger ones.

They are very social creatures and often hang out with other crabs. This gives them an excellent opportunity to play musical shells. They watch for the time when the biggest one among them finds a larger empty shell and when it is ready to move into the new one, the rest all line up in order of size. When the largest switches out, so do the rest and everyone is happy again until the next time. Some say they are more likely to change around a full moon.

There are a lot of different kinds of crabs. Some live in saltwater, some in fresh. Some live on land, but close to water. If they lose a limb or an eye, they can often grow it back after a few moltings. It will form a translucent blob at the stump called a jelly leg. When it molts, a new leg forms from the jelly limb. In larger crabs it can take a few molts before the leg is back to full size.

The crabs are scavengers. Those that live in water are bottom feeders. They clean up the floor of the body of water in which they live. That is why it is not good to eat them. They can carry a lot of harmful chemicals like pesticides, PCBs, dioxin and chlordane. These chemicals are concentrated in the mud, and bottom-feeding fish can accumulate them by swallowing mud while feeding.

All in all crabs are very intriguing creatures. They are also very resourceful. And God has given them a purpose to help clean the earth.