Tag Archives: hermit crabs of okinawa

Gigantic Hermit Crabs Found On Okinawa

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Last year, a friend and I stumbled upon a local beach with gigantic hermit crabs. All of the hermit crabs were found adapting with non-native seashells.

Indonesian hermit crab (Coenbita brevimanus)

Indonesian hermit crab (Coenbita brevimanus)

Where did these shells come from?  The shell shack

The shell shack is an old wooden shed filled with boxes of imported craft shells from the Philippines. The hermit crabs found an opening and took advantage of this real estate.

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Polished muffin (Ryssota ovum)

The most abundant shell was the polished muffin (Ryssota ovum) land snail. This shell is native to the Philippines and is twice the size of any land snail on Okinawa. The muffin shell is a perfect mobile home for the land hermit crabs. It’s lightweight, durable and large.

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perspective photograph

The hermit crabs were healthy and doing well. I didn’t see any hermit crabs adapting with plastic or any twist top caps.

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Land hermit crab (Coenobita cavipes)

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Land hermit crab (Coenobita cavipes)

I also found hermit crabs adapting with a variety of marine shells from the Philippines at the same location.

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Babylonia arealata (Coenobita purpureus)

hermit crab

hexaplex cichoreum (Coenobita cavipes)

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Volema carinifera (Coenobita cavipes)

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Melanella candida (Coenobita purpureus)

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Casmaria erinaceus (Coenobita purpureus)

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hexaplex cichoreum (Coenobita purpureus)

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Turbo chrysostomus (Coenobita purpureus)

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Tonna sulcosa (Coenobita cavipes)

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Learn more about hermit crabs and adaptive behavior ” Crabs with beach trash homes ”

My Mission: To Protect and Preserve the Wildlife of the Ryukyu Islands for Future Generations. – If you would like to join my journey, check out my Patreon https://www.patreon.com/MakeTheSwitch4Nature

Your donations will help conservation initiatives as well as bring solutions to the worldwide pollution issues on our beautiful shorelines.  Thank you for your support, Shawn M Miller.

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The Coconut Crab – Terrestrial hermit crabs of the Ryukyu Islands

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Coconut crabs are the largest terrestrial hermit crabs of the Ryukyu Islands. They are scarce on the Island of Okinawa due to over-hunting. They are sold in local fish markets for high prices. The meat of the coconut crab is sought after and considered a delicacy.  No conservation programs are set in place to protect this native crab. It is currently listed as data deficient on the IUCN list of Threatened species.

  • Scientific name: Birgus latro
  • Common name: Coconut crab, robber crab and palm thief
  • Distribution: Majority of the Ryukyu Islands
  • Habitat: Coastal forest
  • Diet: Seeds, fruit and carrion
  • Average size: 20-40 centimeters
  • Color: Purple, blue or orange
Coconut crab- Okinawa

Coconut crab- Okinawa © Shawn Miller

How to tell the difference between a coconut crab and a hermit crab. They look very similar to the blueberry hermit crab at first, but the coconut crab has protective spines near its eyes. Hermit crabs do not have these spines since they have adapted to retreat into a shell to protect their eyes. The coconut crab does not depend on a seashell as it gets larger. I still have yet to find a juvenile coconut crab adapting with a seashell.

spines that protect the eyes

spines that protect the eyes © Shawn Miller

Terrestrial hermit crabs live in the coastal forest where the treeline and coastline meet. They are the caretakers of the coastal forest. They mainly feed on plants, flowers, fruits, and seeds in the treeline. They also help disperse seeds in the forest, specifically the screw pine tree seeds.

The Climber- robber crab

The Climber- Adult coconut crab © Shawn Miller

Pandanus trees with spiky sword-shaped leaves provide a perfect environment for the Coconut crabs to thrive.

Pandus odifer

Pandus odifer – favorite food © Shawn Miller

A juvenile climbing on Pandanus tree searching for food.

Juvenile coconut crab - Okinawa

Juvenile coconut crab © Shawn Miller

Okinawa’s harsh limestone coastline. The female must make the journey over this rough terrain to lay her eggs in the ocean.

Coconut crab - Onna village

Coconut crab – Onna village © Shawn Miller

Photographed on a white portable outdoor studio for the Meet Your neighbours project. ( Connecting people worldwide with the wildlife in their community )

Coconut crab- MYN technique

Coconut crab- MYN technique © Shawn Miller

In the 1970’s and 1980’s, taxidermy was popular in the Ryukyu Islands. I still find coconut crabs displayed on walls in restaurants and hotels.

Coconut crab mounted © Shawn Miller

Coconut crab mounted © Shawn Miller

Meet Crabzilla! – The most aggressive crab I have encountered on Okinawa.   Coconut crabs are fearless and have bone crushing power. You do not want to get caught by the claw, You play you will Pay!!

Crabzilla -Okinawa

Crabzilla -Okinawa © Shawn Miller

Meet the Bone Crusher! This monster crab was over four pounds. Do not pick these crabs up if you do not know what you are doing. They can crack bones.

Coconut crabs

Coconut crabs © Shawn Miller

Coconut crabs spend their day hiding in burrows.  They venture out searching for food late at night.  This juvenile was found crossing the road.

Let's dance- Coconut crab

Let’s dance- Coconut crab © Shawn Miller

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