Tidal rhythm

Japanese: 潮汐リズム - ちょうせきリズム（英語表記）tidal rhythm

Fiddler crabs and other creatures that live on tidal flats feed at low tide and engage in courtship behavior by vigorously waving their claws, but when the tide comes in, they close the opening of their burrow with a mud lid and shut themselves inside. When fiddler crabs are placed in small containers and their activities are recorded, they are found to be active around the time the tide goes out on the beach where they are collected, which indicates that fiddler crabs have an endogenous rhythm with a period close to the natural tidal cycle, known as tidal rhythm. This type of rhythm has also been found in the activities of fish such as blenny eels and mudskippers, crustaceans such as crabs, hermit crabs, isopods, amphipods, and snail mollusks, as well as in the vertical movement of diatoms, a single-celled organism that lives on sandy beaches.

Source: Heibonsha World Encyclopedia, 2nd Edition Information

Japanese:

干潟に生息するコメツキガニやシオマネキは干潮時には摂食をしたり鋏（はさみ）をさかんに振って求愛行動をしているが，潮がさしてくると巣穴の口に泥のフタをしてその中に閉じこもってしまう。シオマネキを小型容器に入れて，その活動を記録すると，採集地の海岸が干潮になるころさかんに動き回るので，シオマネキが自然の潮汐サイクルに近い周期の内因性リズムを持っていることがわかり，これを潮汐リズムという。この種のリズムは魚類のギンポ，ムツゴロウ，甲殻類のカニ，ヤドカリ，等脚類，端脚類，軟体動物の巻貝などの活動や，さらには砂浜に生息する単細胞生物のケイ藻の垂直移動でも見つかっている。

出典　株式会社平凡社世界大百科事典第２版について　情報

<<: Accommodation paralysis

>>: Tide - tide