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Mangrove Tree Crab

Aratus pisonii


A distinctive crab with a mottled carapace that gets darker as it ages. The younger ones also have more vibrant front claws, as you can see in photo 4. I think what you see on the underside in photo 5 shows the gills. Some were in the trees as is typical of this species, but many were on the ground. I don't normally see so many on the ground. The other strange thing was I came across two that were on their backs on the ground. I flipped them over, and they were alive. One possibility is that they were cold, as this was a fairly cold day, preceded by a couple even colder ones that were freezing temperature.


On the lime rock and empty oyster shells near a mangrove-domainted shoreline. Brackish or salt water nearby. A large part of their diet is mangrove leaves (although they are omnivorous), which is why they prefer to live in the mangroves.

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Machi a year ago

Thanks everyone!

Leuba Ridgway
Leuba Ridgway a year ago

Good series Machi with interesting information. The first time I am hearing of mangrove tree crabs. Thanks.

Maria dB
Maria dB a year ago

Thanks for sharing your observations; that always makes a posting more interesting.

AshleyT a year ago

Your spotting has been nominated for the Spotting of the Week. The winner will be chosen by the Project Noah Rangers based on a combination of factors including: uniqueness of the shot, status of the organism (for example, rare or endangered), quality of the information provided in the habitat and description sections. There is a subjective element, of course; the spotting with the highest number of Ranger votes is chosen. Congratulations on being nominated!

Spotted by

Florida, USA

Spotted on Jan 23, 2020
Submitted on Feb 2, 2020

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