420 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. 



FEEDING. 



Female fiddler crabs feed by scooping up mud with the hairy 

 spoonlike fingers of the chelipeds and carrying it to the mouth, the 

 two hands alternating rapidly. The males use only the small cheli- 

 ped when feeding. The feeding appendages are well suited for the 

 work they have to do. Their fingers are flattened and hollowed in 

 such a way that they form admirable dredges for carrying mud to 

 the mouth. Crabs seldom try to feed when the flats are dry and 

 are most active when the tide is falling. The mouth parts sort over 

 the mud which is scooped up and a mass of rejected material collects 

 below them to drip down or be wiped away now and then by a 

 cheliped. 



'■-^i^fmi,^ 



Fig. 6.— Male fiddlers fighting. 

 Drawn by Tom Jones. 



An examination of the stomachs of several fiddlers showed that 

 the diet is largely vegetarian. The food consists mostly of small 

 algag sifted from the mud. But fiddlers, like most crabs, will eat 

 nearly anything that is cast upon the beach — dead fish, dead crabs, 

 plants, etc. 



DEFENSE AND OFFENSE. 



A fiddler crab lives on a beach crowded among vast numbers of 

 his fellows, but his intercourse with them shows no development of 

 social instincts. He has selected his most suitable habitat, and the 

 fact that he is surrounded by hundreds or thousands of his own kind 

 is more or less incidental. Each fiddler searches the mud around liis 

 hole for food, and " his hand is against every man." He is ever ready 



