Comparative studies of tidal rhythms. VIII. A translocation experiment involving Circalunidian rhythms

One of the earliest experiments that provided support for the exogenous clock hypothesis was a translocation experiment involving fiddler crabs. The activity rhythm of a sample of crabs placed in constant conditions, abandoned (in a week's time) the phase of the tidal cycle to which the crabs had been exposed in nature, and the peaks attuned themselves to the approximate times of lunar nadir and zenith. The study reported in the present paper was an attempt to repeat this interesting and important finding. The effort at replication was unsuccessful. But other more recent findings of tide‐associated rhythms, such as splitting, uncoupling, and temporary arrhythmicity, were confirmed. And an “ultradian”; rhythm was discovered to exist in conjunction with a typical circalunidian frequency.