Burrow tenure in the fiddler crab Uca capricornis

Crabs sometimes vacate their territories due to continued harassment by their neighbours. To determine whether male-female pairs were longer lasting than male-male pairs, we documented the number of crabs that were still present in their same burrow after 24 hours. 20 Focal males were selected: 10 with male nearest neighbours and 10 with female nearest neighbours. The following day, at the same time relative to low tide, we determined whether the crabs were in the same burrows. Data recorded included: the tidal height and time, and whether each crab was present or not. A new set of 20 pairs were marked each day over a period of 26 days.

The data suggests the crabs were less likely to change burrows during neap tides. Males with female neighbours also tended to be more stable than males with male neighbours.