Sally Lightfoot crabs (Grapsus grapsus) are brightly-coloured coastal scavengers, found in the Galapagos Islands and across the western coast of South and Central America. They have an extremely generalist diet, feeding on anything from sea lion placenta to other crabs. This makes them an important part of the ecosystem, as they provide services such as keeping the shore clean of any organic debris and eating ticks off marine iguanas. They are rumoured to have been named after a Caribbean dancer, due to their agility in jumping from rock to rock, their ability to run in four directions and their capacity to climb up vertical slopes. This extreme agility makes them very difficult to catch. Adult crabs show characteristic intense blue and red colouring on their shells, with a white or pale blue underbelly. Younger crabs have darker colouration with red spots, providing a higher degree of camouflage. Every time the crabs moult their shell, the spots become gradually larger, until they obtain the adult colouring.