Vol. L March, IQ26 No. , 



BIOLOGICAL BULLETIN 



NOTES ON THE BEHAVIOR OF THE 

 FIDDLER CRAB. 



JAN B. DEMBOWSKI, 

 M. NENCKI INSTITUTE FOR EXPERIMENTAL BIOLOGY, \V.\KS.\\V. 



There exists already a small literature dealing with habits of 

 fiddler crabs and the general biology of these forms is known 

 fairly well. As far as I am aware none of the various reactions 

 of the animals, however, has yet been studied thoroughly. A 

 careful study of the movements of an animal undoubtedly differs 

 from a general one not merely in bringing some new details, but 

 as well in bringing quite new problems. I quote Schwartz and 

 Safir : "Correlated with the regular recurring changes in the tide, 

 Uca performs its tasks with unchanging regularity, its general 

 behavior never deviating from its standard, never altering from 

 its established method, being almost stereotyped" (18 p. 20). 

 "It has few tasks to accomplish, and does them day in and day 

 out in the same way" (ibid.). From a certain point of view a 

 crab has but a few tasks to accomplish, as digging the burrow, 

 feeding, fighting and performing its sexual activities. From a 

 similar point of view the "general behavior" of man is also a 

 monotony of reactions, like dressing, undressing, eating, walking, 

 talking and sleeping. However we do not consider the man as 

 being a stereotyped automate because we know a lot about our 

 own life, and we know that every one of those reactions may be 

 performed in infinitely different ways. And yet a careful obser- 

 vation of the activities of a fiddler crab leads to very similar 

 conclusions. Every individual digs its burrow but the details of 

 this process may be infinitely various and the behavior of the 

 animal is as far as possible from a stereotype. 



My time being very limited I succeeded in observing but few 

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