Category Archives: Crabs

Friday Fellow: Sally Lightfoot

by Piter Kehoma Boll

Running delicately on the tip of its feet like a ballerina, our first crustacean fellow comes from the Pacific coast of the Americas and is commonly called “sally lightfoot”. Scientifically it is known as Grapsus grapsus, a name that sounds like something gnawing, or grasping, as if it was intended to represent its large claws and small mouth working together to scratch algae from the rocky shores it inhabits.

A sally lightfoot in the Galapagos Islands. Photo by A. Davey.*

A sally lightfoot in the Galapagos Islands. Photo by A. Davey.* (

The sally lightfoot is found on the Pacific coasts of the Americas from Mexico to northern Chile, in the Galapagos Islands and in several Islands in the western Atlantic, such as the Caribbean Islands and the Saint Peter and Saint Paul Archipelago in Brazil. Specimens from the Pacific usually grow up to 80 mm or more in length, while those in the Saint Paul Island are smaller, reaching about 70 mm. Males are slightly larger than females.

As most crabs, the sally lightfoot is a detritivore, feeding on dead animals and other detrites, but seems to be primarily a herbivore, feeding on algae that it scrapes (graps graps graps…) off rocks. It can also, eventually, capture small animals, and there are reports of specimens having a relationship as cleaners with marine iguanas in the Galapagos Islands, scraping ticks (graps graps graps…) of the iguanas’ skin.

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EOL, Encyclopedia of Life. Sally Lightfoot Crab. Available at: < >. Access on May 6, 2016.

Freire, A. S.; Pinheiro, M. A. A.; Karam-Silva, H.; Teschima, M. M. 2011. Biology of Grapsus grapsus (Linnaeus, 1758) (Brachyura, Grapsidae) in the Saint Peter and Saint Paul Archipelago, Equatorial Atlantic Ocean. Helgoland Marine Research, 65 (3): 263–273.

Wikipedia. Grapsus grapsus. Available at: <;. Access on May 6, 2016.

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*Creative Commons License
This image is licensed under a Creative Commons Attribution 2.0 Generic License.

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