A hermit crab prods a larger shell, potentially provoking a new opponent.
LUIS MIGUEL BURCIAGA
(See Alcaraz et al., “Aggressiveness compensates for low muscle strength and metabolic disadvantages in shellfighting: an outcome of the individual’s past,” Behavioral Ecology and Sociobiology, doi: 10.1007/s00265-017-2311-7, 2017.)