in THE SERVICE OF TAILS 8 1 



the same observation may prove true of winged 

 insects having hinder appendages or prolonged 

 abdopiens, such as dragon-flies. " Short-tailed 

 birds," remarks Frank M. Chapman, "generally 

 fly in a straight course, and cannot make sharp 

 turns, while long-tailed birds can pursue a most 

 erratic course with marvellous ease and grace. 

 The grebes are practically tailless, and their flight 

 is comparatively direct, but the swallow-tailed kite, 

 with a tail a foot or more in length, can dash to 

 right or left at the most abrupt angle." 



Many a wild creature trusts to its tail for defence 

 in time of danger, and finds in it an offensive as 

 well as a defensive weapon of no mean worth. The 

 " fighting formation " of the American porcupine, 

 for instance,^ is to turn its back on its foe, hide its 

 head beneath its thorny neck, and strike right and 

 left with its short, spade-shaped tail : this organ 

 is armed with the longest and strongest spines, 

 and it is astonishing what a quick, forcible, and 

 effective blow the little animal can thus deliver. 

 It is probable that the heavy, knobbed tail of 

 the gigantic Mesozoic glyptodon was similarly 

 used. Whales will stave a boat to pieces by 

 a stroke with their powerful flukes ; and the 

 " thresher " shark takes his name from his habit 

 of swinging violently back and forth the long 

 scythe-like prolongation of the upper half of his 

 tail-fin. It is said that he kills small fishes for his 

 1 See also Chapter VII, page i88. 



