Let's find coconut crabs in the jungle of Iriomote Island!

Iriomote Island, a World Heritage Site

Iriomote Island is a very precious place with more than 10 national special natural monuments including the famous Iriomote wild cat, as well as endemic species of animals and plants.
In addition, several other endangered species inhabit Iriomote Island.
It is said that approximately 90% of the plants growing on the island are subtropical primary forests, providing a rich environment for plants in a near-natural state.
Iriomote Island is said to be a continental island separated from the Eurasian continent.
Besides, it will have a unique geographical background, having existed separated from mainland Japan and Eurasia for a million years.
As a result, it is an island of biodiversity with natural environments and ecosystems that are thought to have evolved independently and not found in other areas.
Thus, the area has flora and fauna and unique ecosystems that should be protected, and is academically important and valuable. It is also called Japan's last unexplored region or the Galapagos of the East.
These natural environments would be recognized as having World Natural Heritage value.
For this reason, the area including Iriomote Island has long been nominated as a World Heritage candidate site to UNESCO's World Heritage Center, and in 2021, the area was finally designated as one of the World Natural Heritage sites.

Let's look for the natural treasure coconut crab in Iriomote Island!

Iriomote Island is famous for the Iriomote wildcat, a nationally designated special monument mentioned earlier.
Even if they are not designated as national special monuments like the Iriomote wildcat, Iriomote Island is home to several rare species.
Some of the creatures may also belong to endangered species whose populations are declining.
So here is a summary of information on coconut crabs, which are considered an endangered species.
The coconut crab is currently classified as Endangered II, a category of species that is in increasing danger of extinction.
Although the population of coconut crabs is said to be decreasing due to overhunting, they can be seen on Iriomote Island.
If you go to the trouble of visiting Iriomote Island, you would definitely like to encounter coconut crabs.
So below, we will look at how to meet the coconut crab.

What kind of creature is a coconut crab?

First, let's briefly learn what kind of creature the coconut crab is.
Although the name suggests that the hermit crab is a member of the crab family, it is a member of the hermit crab family.
Hermit crabs are in the order of shrimps, so they belong to the shrimp lineage, not crabs.
Palm crabs live on land, not in the sea.
Their main habitat is coastal forests relatively close to the sea, where they nest in rock crevices and under rocks.
It is also considered to be the largest crustacean living on land.
The larger ones are said to weigh more than 4 kg and exceed 40 cm in length.
Moreover, there are reports that when their legs and scissors are fully extended, some individuals exceed 1 meter in length.
The coconut crabs encountered on Iriomote Island are not super-sized coconut crabs like this, but relatively small ones.
They have strong scissors and are sometimes said to be the strongest crustaceans living on land.
If you encounter a coconut crab, it is important that you do not try to catch it, as you risk being caught with these strong scissors.

The Mysterious Ecology of the Palm Crab

One reason is that coconut crabs are nocturnal, but their biology is not fully understood.
They are still mysterious creatures with many unknowns.
During the day, they hide in the forest near the shore, using rock crevices and under rocks as nests.
Although their name may give the impression that they feed on coconuts, coconut crabs are omnivores.
They have a voracious appetite and will eat anything they deem edible.
For this reason, they are sometimes referred to as "oyster crabs.
The lifespan is estimated to be more than 50 years.
Coconut crabs reproduce by means of eggs, and until recently their spawning grounds were considered to be the sea.
However, in 2008, the Ishigaki branch of the Fisheries Research Institute of the Western Sea Area, Fisheries Research Agency, succeeded in photographing coconut crabs spawning, and it became clear that they spawn on land.

Can coconut crabs be eaten?

Palm crabs can be eaten.
It has been eaten in the Yaeyama region for a long time.
The population of coconut crabs is declining, partly due to overfishing.
The reason they were overfished was probably to eat them.
They are often boiled and eaten. Some say they taste very good, while others say they are unusual and therefore delicious, which may divide people's tastes.

To encounter coconut crabs...

How can we encounter the coconut crab, whose population is said to be decreasing?
Since coconut crabs are nocturnal, it is quite difficult to encounter them by chance during the daytime.
It is also inefficient to search around in rock crevices or under rocks that they use as nests.
So, here is the most reliable way to encounter coconut crabs.

Overnight stay required? Night is recommended!

It can be said that night is the best time to encounter nocturnal coconut crabs.
Although it is not impossible to encounter coconut crabs during the daytime, nighttime is recommended because it is better to encounter active coconut crabs than those hiding quietly in their nests, allowing you to observe coconut crab behavior.
This would mean that an overnight stay is required.
This is because the transportation to Iriomote Island is by boat to/from Ishigaki Island, but the last flight of this boat is in the evening.
To encounter the rare coconut crab, you must spend a relaxing evening on Iriomote Island.

Season when coconut crabs are easy to find

Palm crabs are most frequently sighted during the summer months of July and August.
This may be due to the fact that the breeding season is considered to be from May to September.
This is because during the breeding season, they are more likely to be more active and to have a wider range of activities than usual.
Then the season when you are most likely to find coconut crabs coincides exactly with the summer vacation season.
Visiting Iriomote Island during summer vacation is the best choice to encounter coconut crabs.
During this time of year, you may encounter coconut crabs walking on the road, so if you are traveling by car at night, drive carefully to avoid coconut crabs.
Watching the coconut crabs walk away with a relaxed feeling is an experience that can only be had on Iriomote Island.

Take a jungle night tour!

We have found that the highest probability of encountering coconut crabs is during the summer months at night, but to further increase your chances of encountering them, we recommend that you take a jungle night tour.
If you explore the jungle with a guide who knows the spots where coconut crabs appear, you are fairly certain to see coconut crabs.
By taking a jungle night tour, you can learn about the jungle at night and other nocturnal creatures that appear there.
You may also hear stories about the beautiful starry sky looking up from the jungle.
Since you are staying overnight and participating in the Jungle Night Tour, you should fully enjoy the night in the jungle.
Since this is a night tour, there may be different incidents than during the daytime, and there may be unpredictable problems.
In such cases, having a guide who knows the local area well is a great help.
They will be able to successfully resolve the incident with the appropriate response.

summary

Iriomote Island is an island rich in natural environment with a uniquely formed ecosystem due to its origins and geographical background.
It is probably an island of biodiversity, as it is home to a nationally designated special natural hazard.
Because of this precious natural environment, the site is considered so academically important that it has been called the Galapagos of the East.
Although coconut crabs are on the endangered species list because their population has been decreasing due to overhunting, you can encounter coconut crabs on Iriomote Island.
The best way to encounter coconut crabs is on a jungle night tour.
In the jungle night tour, you will be able to meet not only coconut crabs but also other nocturnal creatures and fully enjoy the night of Iriomote Island.
Why don't you visit Iriomote Island and see the rare coconut crab?