AbstractGhost crabs are distributed worldwide on sandy beaches, and several studies have associated the number of ghost crab burrows with the levels of anthropogenic impacts on the beaches under study. However, our results show that the use of ghost crab Ocypode quadrata burrows to assess levels of anthropogenic impacts on sand beaches may not be accurate, as previously thought, because the number of burrows does not represent an estimate of the population size. In addition, we propose three

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... otheses to explain the extremely low number of individuals/number of burrows ratio: the "secret chamber", the "multiple openings", and the "one crab, several burrows" hypotheses. We also observed an unusual sex ratio.