Clocks in Other Living Things

Of course, man is not the only living creature endowed with built-in clocks. Swallows return each spring to Capistrano, California, U.S.A., on time. There are oysters that open their shells at high tide and close them at low tide, regardless of the coastal areas. Various plants open by day and close at night.

Why, so well timed is the appearance of grunion (fish) on Southern California beaches for their ‘mating dance’ that newspapers publish the precise time of their arrival. Even certain microscopic algae have a 24-hour rhythm, giving off a phosphorescent glow for 12 hours of the night.

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Animal Clocks

◻ Bees: “Train their own internal clocks to be at the right place at the right time to reap their honey harvest.”

◻ Tinamou: “Three-hour bird” of Panama sings every three hours, day and night. You can set your watch by it.

◻ Flicker woodpecker of Canada and the United States: One was observed to quit its activities on schedule at 3:35 each afternoon without fail.

◻ Salmon: Internal clocks indicate time to return from the sea to the river where they were spawned.

◻ Palolo worms in the Fiji Islands: Surface and begin their reproductive activities as dawn breaks on nights of third quarter of moon during months of October and November.

◻ Fiddler crabs: Have a precise 24-hour schedule of turning dark during day and pale at night. Color changes are geared to the sun and feeding habits to the moon.