The Life Cycle of Crabs

Crabs go through many different stages of life before they grow up into adults, just like us humans. (You are human right?)

In some of the early stages of a crab’s development, they don’t look like crabs at all. They become more recognisably crabby the older they get, a lot like frogs as they turn from tadpoles into frogs.

After two adult crabs have mated successfully, the female begins to grow thousands of eggs on her underside. These eggs can take between 2 and 9 months to develop fully.

You can tell the difference between the sex of crabs based on how wide their abdomens are - though you’ll never work out their gender.

After the eggs are released they float around until they develop into what we call Zoeae. Zoeae are tiny - only 0.25mm - their size means they can hide from predators.

After a while, and depending on the water conditions, the Zoeae will develop into what we call Megalops. As a rule of thumb, the warmer the water, the faster crabs move through their larval stages.

As the crab moves into the Megalops stage, it starts to look a lot more like a crab. By this point it is around 1mm in size.

A few molts later and our Megalops has grown into what we would recognise as a crab, just in miniature. From here our juvenile crab simply needs to molt and grow bigger before reaching sexual maturity after 12 - 18 months.

After that, it starts all over again!