Red crab migration on Christmas Island

Photographer James D Morgan chronicled the annual migration of the red crabs across Christmas Island for Australian Geographic, documenting the amazing swarms of adorable scuttlers as they rush to the sea in order to reproduce:

The mass migration is headed by the males, quickly followed by the females. The crabs spend several painstaking weeks scuttling to the ocean, which can be as far as 9 km away.

Along the way they face numerous hazards. While the locals do the best as they can, according to ranger Max Orchard each year up to half a million crabs never return from their perilous journey. Many of these casualties fall under the wheels of vehicles as they attempt to traverse local roads, while others are attacked by yellow crazy ants.

Once the males arrive at the sea, they dig special burrows, where mating takes place once the females arrive. After the deed is done, the males begin the arduous journey back inland while the females remain in the burrows for about two weeks, laying eggs and waiting for them to develop. The eggs are held in a brood pouch – located between the female crab's abdomen and thorax – which can each hold as many as 100,000 eggs.

When the time is right, just before dawn at high tide, the egg-laden females descend to the waterline to release their eggs, a process that can occur over several nights.

March of the Christmas Island crabs

(via Neil Gaiman)

(Image: Red crabs migrate through in the middle of the island, James D Morgan )


  1. Every time I see something on this I just wonder if these guys are tasty or not. From what I understand they’re technically speaking edible, but I can never find anything on whether they’re worth eating or if there is any tradition of eating them.

    1. You don’t want to interfere with the ‘appeasement of Dagon’ procedure. Just don’t. 

    2. Though you can eat the red crabs I’m told that they aren’t very nice. Apparently they taste rather muddy. There are other crabs on the island that are often eaten, including a few protected species that are euphemistically called ‘forest lobster’ or similar.

      1. I grew up on Christmas Island, and while it may not be true, my parents always told my sisters and I that they were poisonous, as were coconut crabs (possibly the forest lobster you’re referring to.) From what I understand, none of the crabs there were edible, although that may just be because of the flavour. I remember people eating the ocean crabs (more than a few got ciguatera.)

        Coconut Crab: 

          1. It may be cold comfort, but judging by the size of the handles that’s not a full-sized garbage can.

          2. Yeah, I know. It looks like it’s about 16 inches high. I’m surprised that nobody’s photoshopped it to fix that.

        1. Coconut Crab is supposed to be delicious, but apparently it can become poisonous in places where they habitually nosh on poisonous feed (a bit like blow fish I guess). So, if MathewClay is right, your parent probably weren’t stearing you wrong. Red crab = disapointingly nasty, coconut crab = potentially toxic. And then you mention ciguatera. Remind me not to visit that part of the world.

    1. They’re full on when you live on the island. Some of the homes on top of the hill are built directly between the bulk of the rainforest and the bay – you leave your front and back doors open, and close of all the other doors inside, then let them just file through. School is cancelled for that week, as you can’t get to the school without crushing millions of crabs. The roads turn red with a sea of crabs. And then the babies come crawling out of the ocean, up to the jungle. They are everywhere.

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