Last Updated on: 15th October 2023, 06:06 pm
The reproductive method of hermit crabs involves laying eggs, not giving birth to live young.
After two hermit crabs mate, the female can carry up to 50,000 eggs. She carries the eggs for about a month before laying them in the ocean. The eggs hatch upon contact with salt water.
After a female lays eggs in the sea, she seeks her next mate. The hatchlings are known as zoea, the first life stage of three that must be negotiated to evolve into an adult hermit crab.
Hermit crabs don’t play an active role in raising their young. Few hermit crabs survive the process.
How Do Hermit Crabs Reproduce?
The breeding process involves a single male and female and the release of spermatozoa. Once sperm enters the female’s reproductive organs, known as the gonophores, it fertilizes the eggs.
Hermit Crab Mating
Hermit crab egg production involves mating. The Journal of Crustacean Biology explains how females must accept a male’s invitation to mate.
A female hermit crab in season releases distinctive pheromones that capture the attention of males. Male hermit crabs invite the female to breed by rapping on her shell.
Male hermit crabs may fight over who’ll mate with a female. A male who wishes to breed may also ‘guard’ the female, following her to prevent access to other males.
If the female is unreceptive to breeding, she hides in her shell until the male loses interest. She’ll emerge and instigate the breeding process if she wants to mate.
Hermit crab breeding takes place within the shell for the safety of both genders.
A hermit crab’s penis measures roughly half its abdomen. This means it can locate and enter a female’s gonophores – found above the rearmost legs – without leaving its shell.
Will My Captive Hermit Crabs Mate?
In most circumstances, pairing male and female animals in the same habitat creates a risk of breeding. This isn’t true for hermit crabs, who seldom mate in captivity.
Female hermit crabs still enter season while living in captivity, so males will attempt to mate.
The female will reject advances and hide in her shell. Females move in and out of season every 3 to 4 days, and males lose interest as soon as the pheromones cease.
What Do Hermit Crab Eggs Look Like?
Female hermit crabs carry eggs in a sac found on the side of the abdomen. Once a female is fertilized, the eggs will become visible. As the eggs grow in size, they’ll become more prominent.
Female hermit crabs are initially bright red, fading to a deep gray as they near egg-laying.
Where Do Hermit Crabs Lay Their Eggs?
Females lay their eggs in the ocean, so captive hermit crabs rarely mate.
The female understands the difference between a bathtub of saline water and the sea. The lack of expansive salt water makes breeding unappealing.
A female may lay her eggs immediately if the tide is low. If necessary, the female will toss her eggs from the shore or climb a tree and release them into the ocean.
How Often Do Hermit Crabs Lay Eggs?
Hermit crabs can reproduce and lay eggs throughout their lifetime. Females enter into season at least once a week, and it takes 1 month for eggs to develop and be ready for hatching.
This suggests that hermit crabs can lay more than 10 egg clutches annually.
The lifespan of wild hermit crabs varies, but it could be as long as 30 years. This means that a healthy female could lay over 300 clutches of eggs in her lifetime.
How Many Eggs Do Hermit Crabs Lay?
Female hermit crabs can carry 1,000 to 50,000 eggs per clutch. The male and female’s age, size, and fecundity will affect how many eggs are produced.
Hermit crabs can reproduce as soon as they reach adulthood. Larger females can carry more eggs than their smaller ones, producing more eggs as the hermit crab grows and molts.
While female hermit crabs prefer to mate with larger males, Proceedings of the Royal Society explains that smaller males are more fertile and likelier to produce larger clutches of eggs.
How Long Does it Take for Hermit Crab Eggs to Hatch?
A female carries eggs in her sac for around 1 month. She’ll move toward the ocean when ready to lay her eggs. The eggs will hatch almost immediately upon contact with salt water.
If a female hermit crab carries eggs, she’ll avoid saltwater so that her eggs don’t hatch early.
What Happens When Hermit Crab Eggs Hatch?
Once hermit crab eggs are laid, the mother abandons the clutch.
From this point, the hatchlings must survive three early life stages:
Stage One – Zoeae
When hermit crab eggs hatch, zoea emerge. Zoea are tiny larvae that rise to the top of the ocean, where they float alongside plankton.
Few hermit crab hatchlings survive beyond the zoea stage. Their diminutive size and proximity to plankton mean they’re usually eaten by passing fish and whales.
If the zoea remains alive for 30 to 60 days, it’ll head to the shore. Upon reaching dry land, the zoea commences the next stage of evolution (Megalopae).
Stage Two – Megalopa
Megalopae live on the shore and are impossible to see with the human eye.
The life expectancy for megalopae is short, rarely more than a few hours. They adopt a “survival of the fittest” philosophy, frequently cannibalizing each other.
A megalopa will burrow under the sand if it makes it that far. A megalopa will remain hidden underground for about 30 days and evolve into a tiny hermit crab.
Stage Three – Juvenile
Juvenile hermit crabs aren’t born with shells and are vulnerable to predators due to their small size.
A juvenile will emerge from the sand once it evolves from the megalopa phase and seek a suitable shell. It’s unlikely to survive unless it finds a gastropod shell for protection.
Hermit crabs molt regularly in the early months of life. Each molt leads to an increase in size and a stronger exoskeleton. Once a hermit crab reaches 3.5mm in length, it’s an adult.
An adult hermit crab will join a colony and seek to breed.
The life cycle from zoea to hermit crab is dangerous, and few hatchlings survive long enough to evolve. This is why hermit crabs lay so many eggs to ensure the propagation of the species.
