680 THE PHYSIOLOGY OF REPRODUCTION 



the queen ant being known to live for several years (in one case 

 for fifteen years), whereas the male ant survives for only a few 

 weeks. 



Among fish, pike and carp are usually said to attain to great 

 ages and even to live for centuries, but there are few accurate 

 data. 



Among reptiles, crocodiles and tortoises are known to have 

 long lives, a tortoise from the Galapagos Islands being stated 

 to have lived for 175 years. 



The length of life in birds has been discussed by Gurney,^ 



Fig. 153. — Land tortoise {Testudo mauritanico), aged at least 

 eighty-six, belonging to M. Elie MetchnikofE. 



{From Metchnikoff's " The Prolongation of Life," by permission of Mr W. Heinemann.) 



who cites several examples of great longevity, but the more 

 usual duration of life is from fifteen to twenty years. Canaries 

 are stated to have attained to twenty years of age, a herring gull 

 to forty-four, an imperial eagle to fifty-six, a heron to sixty, an 

 eagle owl to sixty-eight, a raven to sixty-nine, a swan to seventy, 

 and a goose to eighty. MetchnikofE records a case of a parrot 

 which lived for eighty- two years. 



Mammals on the average appear to have considerably shorter 

 lives than birds. According to Weismann, whales live for some 

 hundreds of years, but it is difficult to see how this can be 



^ Gurney, " On the Comparative Ages to which Birds Live," Ibi/>, vol. v., 

 1S99. 



