SYNCHRONISM AND SYNCHRONIC RHYTHM IN 

 THE BEHAVIOR OF CERTAIN CREATURES 



It is a matter of common experience to observe in- 

 stances of synchronous behavior and expression among 

 creatures. In such instances an entire group of creatures 

 may react simultaneously to the same external stimulus. 

 A flock of birds will arise from the ground and dash away 

 at the first signal of danger, or a school of fish will swerve 

 as a unit from a stick pushed toward them. In the same 

 way certain frogs in a pool may be started into a brief, 

 explosive chorus of simultaneous croaking by the notes of 

 a single individual. After a brief period during which 

 all have expressed themselves, silence ensues until the 

 next singing-reflex is unlocked by the croaking of another 

 individual. In New England I have heard the wood frog, 

 or so-called clucking frog {Rana sylvatica) give rise to 

 just such outbursts of simultaneous clucking, started 

 either by the frogs themselves or by my giving an imita- 

 tion of their notes during an interval of silence. This 

 habit of singing in concert is not unusual among certain 

 species of frogs, and is mentioned by D. D. Cunningham 

 (1903) in his excellent book, ''Some Indian Friends and 

 Acquaintances." He says: 



Such utterances recur several times in succession; a short pause fol- 

 lows and then the conversation begins again. The curious thing is that 

 all the perfoi 



with those of general iiproar. The phenomenon is parallel to that of 

 the synchronous luminosity that sometimes occurs so markedly in 

 groups of fireflies. 



In these instances syncliroiiism i> iiiaiTitainod at inter- 

 vals, but there is no fcuiilar i-liytliinic expression witliin 

 the group itself. Each i'lou' croaks in its own way, until 

 a perfect ba1)el of noise is ))roduced. 



Similar synclironon< outbursts of sound also occur 

 among tlie tini^ical in>ccts. The tendency to respond to 

 the notes of their kind is very strong, and a single singer 

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