Poster Girl of Tropical Summer: Land Crabs
Tara A. Spears
“There she was just a walkin’ down the street…clicking her pinchers singing do wah diddi…”
When it comes to cool and unusual creatures, the tropic excels in bizarre species. My favorite is the Mouthless Land Crab/ Cangrejo Azul, which is typically active at night unless it is the migration period after the rains start. To me, no matter what the weatherman says, it’s not the official rainy season until I see the crabs. C. Crassum is general shy preferring to burrow in the jungle but during the migration time you will can see them journeying any time of day on their way to and from the ocean to reproduce. I’ve had crabs resting in the dog’s water dish, an outdoor fountain and one year even joining me in the shower! The hotels and houses of Jaltemba Bay are between the Land Crab’s habitat and the ocean so expect to see them when the rains first start. Please don’t kill them, but relocate any crabs to where they can continue their journey.
Look at that face! It’s a combination of Star Wars chic and exotic beauty. The Mouthless Land Crab is easy to identify because it is a mid to large-sized crab that is characterized by having an oval, thick, inflated shell that is wider than it is deep and one claw (chelae) that is larger than the other. They have a wide forehead with eyes on stalks that are set near the sides of the body. Mouthless Crabs have a purplish-blue shell, red legs and whitish pincers. The males are brighter in color than the females. The females normally outnumber males by a ratio of three to two.
The Mouthless Land Crab resides in coastal environments that may include brackish water, estuaries, and mangroves within fresh water river basins adjacent to salt marshes as they require access to the sea for breeding and larval development. They reside in burrows with multiple entrances that they build in dry mud within plant roots, including mangroves; they are also found around rocky crevices. 
According to Crab.org, what’s ecologically beneficial about C. Crassum crab is that it’s a jungle garbage disposal. Not only is this crab cannibalistic, feeding on insects and carrions, but it eats leaves and fruits. Young individuals are often very colorful (leading to a level of popularity in the pet trade), but as land crabs grow older their colors tend to fade. At all ages, males are brighter than the females. In the wild, C. Crassum crabs are also an important food source for alligators, birds and raccoons.
It’s good to know that the Mouthless Land Crabs are maintaining their numbers and considered to be of Least Concern on the extinction list. But, there are still pressure on this species as they are an important food source in southern Mexico. The crabs are caught by hand and sold fresh in local markets. Land crabs are subject to a high level of illegal commercial exploitation for the pet trade due to their attractive colors. Lastly, the Land crab is loosing habit due to all of the coastal building in Mexico.
If you encounter one of these exotic creatures on your morning walk, don’t expect a welcome reception. Imediately the crab freezes and takes a defensive posture with its claws up, ready to battle. Spunky little creatures! Snap a picture and let them continue their journey.