Mangrove Tree Crab
Aratus pisonii
An agile coastal crab that climbs high through red, black, and white mangroves across southern Florida.
Mangrove Tree Crabs live above the waterline on mangrove trunks, prop roots, and branches. Their flattened bodies and long pointed legs help them cling to bark and leaves while tides rise below.
They graze mangrove leaves, flowers, algae, carrion, and small animals. When threatened, a crab may race around a trunk or drop toward the water, where fish and other predators wait.
Habitat:
Estuaries and Bays, Mangroves and Salt Marshes
Area / Range:
South Florida, Florida Keys, Atlantic Coast, Gulf Coast
Diet:
Omnivorous grazer that eats mangrove leaves, algae, fungi, flowers, detritus, small invertebrates, and carrion.
Behavior:
Climbs rapidly through mangrove branches, feeds mostly above the waterline, and moves with the tide. It hides in bark crevices and around prop roots when disturbed.
Daytime, Nighttime, Dawn and Dusk
Active Times:
Best time to see:
During low or falling tide on mangrove trunks and leaves in shaded estuaries and coastal boardwalk areas.
Florida Native Status:
Native
Conservation Status:
Not listed; long-term security depends on healthy mangrove forests, clean estuaries, and natural shorelines.
Safety Level:
Low
Safety Information:
Observe without handling. Small claws can pinch, and climbing on mangrove roots damages habitat and creates a fall hazard.
Benefits to Property:
Recycles mangrove leaf material, transfers nutrients through the food web, and provides prey for fish, birds, raccoons, and other coastal wildlife.
Property Concerns:
Causes no structural damage. Large numbers usually indicate nearby mangrove habitat and tidal access rather than an infestation.
Fun Fact:
- It spends much of its life above the water.
- Its colors blend with mangrove bark and leaves.
- It can move quickly around narrow branches.
Wildlife Laws:
Do not damage mangroves to reach wildlife. Florida mangrove trimming and alteration are regulated, and collecting animals in parks or protected areas requires applicable permission.
Identification:
Small flattened crab with a mottled olive, brown, gray, or greenish shell, long slender legs, and reddish to purple claws. Adults often sit on mangrove branches well above the water.