There are 10 criteria you should consider when selecting alternative shells for your land hermit crabs.
Ask yourself the following questions as you shop:
1. Does the shell have an appropriate aperture?
If you are shell shopping for a purple-clawed hermit crab (Coenobita clypeatus), choose a shell that has a circular aperture, typical of the shells found in his native Caribbean environment and most fitting for his body style. Otherwise, if you are shopping for a brown-clawed Ecuadorian hermit crab (Coenobita compressus), select shells that have an oval aperture, which is likewise typical of the shells found in his native West Coast environment and most fitting for his body style. Both species of hermit crabs can live successfully in a shell with a circular or oval aperture, but typically each species has a different preference. Avoid shells with slot-like apertures.
2. Is it the right size?
A well-fitting shell is one into which a hermit crab can retract his whole body and can "seal closed" the aperture with his largest claw. A new shell should have an aperture that is approximately ΒΌ-inch larger than the aperture of your hermit crab's current shell. If his current shell appears to be too bulky and cumbersome, then buy a smaller shell. Providing your crab with different shells of the same size will allow him to choose a shell by its style, instead of its size.
3. Is the spire on the shell's right side?
Because a hermit crab's abdomen curves to his right, shells should be purchased that curve in the same direction. Although most shells typically have the spire on the right side (which would be to our left as we look at the shell's opening), some shells have the spire on the opposite side or do not have a spire at all, so be sure to check them.
4. Is the shell free of holes and cracks?
Examine the shells you are considering to make sure they have no holes or cracks. Shells that have holes or cracks may prevent a hermit crab from being able to store a reservoir of water in his shell. This reservoir of water is used as a temporary drinking supply and as a method for keeping his gills moist and his shell clean.
5. Does the shell provide ample room for his abdomen?
The size of a hermit crab's hidden abdomen is typically the thickness and length of two of his walking legs. Once inside a shell, a hermit crab will coil his abdomen neatly into the spire of the shell. Looking at the shell, estimate if you think his abdomen will fit comfortably in the diameters of the sutures. The shell should probably have at least two to three full sutures to be adequate. This is a very important shell feature which most shell shoppers forget to analyze.
6. How are the weight of the shell and the thickness of the shell walls?
Make sure that the shells you choose are not too heavy for your hermit crab to carry around. Some prefer shells with thin walls because they are light and easy to transport. However, shells whose walls are too thin will chip easily, causing some hermit crabs to avoid them. Typically, most hermit crabs prefer shells with medium to thick walls.
7. Can his eyes look out comfortably?
Avoid shells with lengthy outer lips which cause low overheads that may make it difficult for a hermit crab to be comfortable with his eyestalks out while walking.
8. Does the shell pass the "tabletop test"?
If you place a prospective shell on a tabletop or flat surface with its aperture flush to the surface, it should remain in much the same position as it would be if a hermit crab were occupying it; that is, it should remain with the shell spire facing out to its right (our left). Shells that are less conducive to a hermit crab will have the spire pointed more upwards when placed in this position. Shells that have the spire facing somewhat upward when placed on a flat surface are less comfortable to a hermit crab simply because his abdomen curves to the right-not upwards.
9. Does the shell have too much unusable space?
Shells that have a very lengthy spire or left canal may be unnecessarily cumbersome for your hermit crab to tote around. Shells with long canals can be filed down (please never do this while the shell is occupied), but this usually leaves a wide opening on the side of the shell, making the hermit crab feel less protected. Therefore, choose a shell that does not have too much unusable space.
10. Does the shell have a smooth interior and aperture?
Hermit crabs will avoid shells that have rough interiors and apertures. A shell with a smooth interior and aperture will allow a hermit crab to retract into the safety of his shell quickly and comfortably.
Ask yourself the following questions as you shop:
1. Does the shell have an appropriate aperture?
If you are shell shopping for a purple-clawed hermit crab (Coenobita clypeatus), choose a shell that has a circular aperture, typical of the shells found in his native Caribbean environment and most fitting for his body style. Otherwise, if you are shopping for a brown-clawed Ecuadorian hermit crab (Coenobita compressus), select shells that have an oval aperture, which is likewise typical of the shells found in his native West Coast environment and most fitting for his body style. Both species of hermit crabs can live successfully in a shell with a circular or oval aperture, but typically each species has a different preference. Avoid shells with slot-like apertures.
2. Is it the right size?
A well-fitting shell is one into which a hermit crab can retract his whole body and can "seal closed" the aperture with his largest claw. A new shell should have an aperture that is approximately ΒΌ-inch larger than the aperture of your hermit crab's current shell. If his current shell appears to be too bulky and cumbersome, then buy a smaller shell. Providing your crab with different shells of the same size will allow him to choose a shell by its style, instead of its size.
3. Is the spire on the shell's right side?
Because a hermit crab's abdomen curves to his right, shells should be purchased that curve in the same direction. Although most shells typically have the spire on the right side (which would be to our left as we look at the shell's opening), some shells have the spire on the opposite side or do not have a spire at all, so be sure to check them.
4. Is the shell free of holes and cracks?
Examine the shells you are considering to make sure they have no holes or cracks. Shells that have holes or cracks may prevent a hermit crab from being able to store a reservoir of water in his shell. This reservoir of water is used as a temporary drinking supply and as a method for keeping his gills moist and his shell clean.
5. Does the shell provide ample room for his abdomen?
The size of a hermit crab's hidden abdomen is typically the thickness and length of two of his walking legs. Once inside a shell, a hermit crab will coil his abdomen neatly into the spire of the shell. Looking at the shell, estimate if you think his abdomen will fit comfortably in the diameters of the sutures. The shell should probably have at least two to three full sutures to be adequate. This is a very important shell feature which most shell shoppers forget to analyze.
6. How are the weight of the shell and the thickness of the shell walls?
Make sure that the shells you choose are not too heavy for your hermit crab to carry around. Some prefer shells with thin walls because they are light and easy to transport. However, shells whose walls are too thin will chip easily, causing some hermit crabs to avoid them. Typically, most hermit crabs prefer shells with medium to thick walls.
7. Can his eyes look out comfortably?
Avoid shells with lengthy outer lips which cause low overheads that may make it difficult for a hermit crab to be comfortable with his eyestalks out while walking.
8. Does the shell pass the "tabletop test"?
If you place a prospective shell on a tabletop or flat surface with its aperture flush to the surface, it should remain in much the same position as it would be if a hermit crab were occupying it; that is, it should remain with the shell spire facing out to its right (our left). Shells that are less conducive to a hermit crab will have the spire pointed more upwards when placed in this position. Shells that have the spire facing somewhat upward when placed on a flat surface are less comfortable to a hermit crab simply because his abdomen curves to the right-not upwards.
9. Does the shell have too much unusable space?
Shells that have a very lengthy spire or left canal may be unnecessarily cumbersome for your hermit crab to tote around. Shells with long canals can be filed down (please never do this while the shell is occupied), but this usually leaves a wide opening on the side of the shell, making the hermit crab feel less protected. Therefore, choose a shell that does not have too much unusable space.
10. Does the shell have a smooth interior and aperture?
Hermit crabs will avoid shells that have rough interiors and apertures. A shell with a smooth interior and aperture will allow a hermit crab to retract into the safety of his shell quickly and comfortably.
Some shells are better than others! Make sure the shells you buy for your hermit crabs meet all 10 criteria listed on this page!
