Male vs Female Hermit Crab: How to Tell What You Have and Other Key Differences

Hermit crabs are crustaceans with over 800 species including male and female sexes. They belong to the class Malacostraca and have a global presence with their average lifespan reaching about 40 years in the wild. 

While they are mostly the same and hard to distinguish, male and female hermit crabs have some differences.

This article focuses squarely on the male and female hermit crab as well as their differences and peculiarities. 

Comparing Male and Female Hermit Crabs

Male and female hermit crabs have a few differences ranging from behaviors to sexual organs to physical appearance among others. Below is a table showing the few differences between them:

The Major Differences Between Male And Female Hermit Crabs

Scientifically known as Paguroidea, male and female hermit crabs have a few differences ranging from sexual organs to certain physical characteristics and mating behaviors that can help decipher their rather hard-to-tell sexes. 

Below is a detailed discourse on these subtle differences. 

Male Hermit Crab Vs Female Hermit Crab: Physical Features

Truth is, at first glance, it is almost impossible to tell the correct sex of a hermit crab. That’s because they share sameness in aspects such as:

• Habitat- Coastal waters
• Prey- Fish, plankton, and worms
• Diet– Omnivorous
• Skin- Shell
• Weight- 200-500grams (7-18oz)
• Color- Brown, Yellow, White, Blue, Red, Green, Orange, Pink. 

So, going by the above alone, it would be impossible to figure out the sex of a hermit crab. However, despite the seeming similarities, some physical differences can help distinguish the sexes. 

One of the easiest ways to tell the sex of a hermit crab is by checking their legs. If the legs are hairy, then it’s most likely male and if they are smooth, it’s most likely a female hermit crab. Also, while female hermit crabs have legs on the left side of their abdomen, male hermit crabs do not. 

Another difference is seen in the presence of appendages; male hermit crabs have no appendages, while females have three different appendages on the left side of their abdomens. 

Male Hermit Crab Vs Female Hermit Crab: Sexual Organs 

You could also tell the sex of hermit crabs by taking a look at their sexual organs. Male hermit crabs have a penis that is below their fifth pair of legs. Some scientists found that the penis can grow as large as 60% of the hermit crab’s body length and this has been described as an evolutionary ploy to protect the shell. Large penises help them to mate without having to leave their shells, which if they did, would likely be taken over by a rival hermit crab. 

Female hermit crabs, on the other hand, have sexual organs known as gonophores. There are two tiny openings right atop the third pair of legs. The openings are infinitesimal and may require a magnifying glass for a proper view. 

Male Hermit Crab Vs Female Hermit Crab: Behavior

Male and female hermit crabs also have some behavioral differences, although scientists often deem these as unreliable sexing factors. 

The male hermit crabs are less likely to explore new terrains and habitats. Once they have found a spot, they prefer to remain there and just stick it out as long as there is no mortal threat to their existence. 

Female hermit crabs, on the other hand, are more likely to find new terrains and habitats. Unlike their male counterparts, they are more daring and explorative. Their adventurous behavior also helps them find different hiding places. 

Male Hermit Crab Vs Female Hermit Crab: Growth Rate

Male and female hermit crabs grow differently, more often than not. Males are known for having spectacularly fast growth with frequent molting. Females, however, grow slower because they often breed as early as the first year of their existence. A male hermit crab will very likely be bigger than the female with hairy legs, while females have smooth, hairless legs. 

Male Hermit Vs Female Hermit Crab: Mating Behavior And Reproduction

For hermit crabs, there is a mating season that comes up once a year and during these seasons, male and female hermit crabs often exhibit distinct behaviors as we are about to see. 

Like most male animals, the male hermit crabs are very keen on mating and reproduction even when they are not in their preferred habitats. The female hermit crabs, on the other hand, do not like to mate and breed when they are in captivity. 

Also, male hermit crabs tend to grow in size and mass during mating seasons, while the size and mass of female hermit crabs stay consistent. 

While they are often very excited about mating and reproduction, male hermit crabs lack the ability to produce sexual pheromones. Female hermit crabs can however produce sexual pheromones as long as the conditions are right and they are willing to mate. 

Again, like most male animals, the contribution of male hermit crabs to reproduction is seen during mating. This happens with the male grabbing the female with one claw and pulling the female back and forth amidst continuous stroking activity.