452 DR. p. CHALMERS MITCHELL ON LONGEVITY AND 



fact that they are a successful group, with remarkable power of 

 adaptation to different envii-onments. 



The most important practical result is the very striking series 

 of contrasts between the average and maximum durations of those 

 animals which have had free access to fresh air and of those which 

 have been deprived of such access by detention in heated houses, — 

 a contrast that seems independent of the natural habitat of the 

 animals in question. 



,^-p . p,-j-,Q No, of Av. diav. Max. dur. 



xi X xiAL-bjO. Iiidiv. in months. in months. 



JIy7'ax capensis {GR.])e ILyi'ixx) 10 15*2 50 



H.dorsalis (Dorsal „ ) 2 18-5 36 



I can find no other records which would throw light on the 

 potential longevity of these animals, the zoological position of 

 which is very doubtful. It is impossible to tell their ages 

 if they are adult on arrival, and therefore the maximum 

 duration of just over four years gives no reliable indication of the 

 potential longevity. As these animals have a most complex and 

 capacious hind-gut, and as they are vegetable-feeders, a high 

 viability or great longevity is not to be expected, according to 

 MetchnikofF's views. In the period covered by these figures, the 

 Hyraces were almost invariably given access to open air. 



Oapt. Stanley Flower's figures are lower. 



PROBOSCIDEA. 



Elephas africanus^Aivicixxx Elephant) 

 E. indicus (Indian „ ) 



Metchnikoff has already pointed out that there is no exact 

 basis for the popular ascription of very high potential longevity 

 to these animals. It used to be thought that they could live for 

 several centuries. Flourens, using his formula based on the age 

 at which the epiphyses unite with the long bones, set down 150 

 years as the limit of their age. Indian natives ascribe a limit of 

 from 80 to 150 years. On the other hand, the official list of the 

 Indian Government, cited by Brehm, shows that of 138 elephants 

 only one lived for more than 20 years after it had been purchased. 

 Twenty to twenty-five years' duration in a menagerie is regarded 

 as good. The record in this list of about 24 years has been far 

 surpassed by a female Indian Elephant, broiight as a young 

 animal by the Prince of Wales from India in 1876, and still alive 

 and apparently in quite good condition in our Gardens, although 

 its age is certainl}^ over 34 years. I agree with the genei'al con- 

 clusion of Metchnikoff, that elephants, in proportion to their 

 size, have neither a high potential longevity nor a good viability, 

 not much more than a hundred years being the probable age limit, 

 and twenty to thirty years a fair average dui-a,tion. 



