"Grapsus grapsus is one of the most common crabs along the western coast of the Americas. It is known variously as, ""red rock crab"", ""abuete negro"", and along with crabs such as Percnon gibbesi as, ""Sally Lightfoot""."
These tiny little crabs were everywhere, including in the trees, which they nimbly scuttled through as easily as if they were on the ground. They were very intelligent and reactive, quick to dart away if they noticed you staring at them.