The Biology of Senescence 



begins with the enormously painstaking studies of Chalmers 

 Mitchell (1911) and Flower (1925, 1931, 1935, 1936, 1937, 

 1938 x ) in purging a vast body of legendary and anecdotal 

 material which encumbered the subject. Much of this legendary 

 material unfortunately persists in other books and papers 

 {Tabulae Biologicae — Heilbrunn, 1943; Nagornyi, 1948; Ham- 

 mond and Marshall, 1952; Schmidt, 1952; Wurmbach, 1951) 

 deriving their data from Korschelt (1922). The scepticism of 

 Flower's papers was very valuable, in view of the exorbitant 

 claims made for parrots, elephants and so on, but it seems 

 probable that birds, in particular, are in fact capable of living 

 considerably longer than Flower's maximum figures suggest. 

 Better data may, in time, become available, though the value 

 of such records is still not sufficiently widely appreciated and 

 many opportunities must have been lost through failure to keep 

 track of individual specimens. No recent writer has dealt equally 

 painstakingly with the longevity of invertebrates. 



The data on vertebrate senescence which follow are those of 

 Flower, except where otherwise stated. Some more recent re- 

 cords have been added, including a number derived from the 

 series of longevity studies published by the Penrose Laboratory 

 of the Philadelphia Zoo in the years prior to 1942 (Duetz, 1938, 

 1939, 1940, 1942). 



2-2-1 MAMMALS 



The longest-lived species is man. Elephas indicus is known to 

 reach 60 years: a few individuals may reach or exceed 70 in cap- 

 tivity (77? — Mohr, 1951). The only other mammals which are 

 known to approach or exceed 50 years are the horse, hippopota- 

 mus (49 years 6 months: 1953 — Ann.Rep.N.Y. zooL Soc, 53, 12), 

 Rhinoceros unicornis (49 years — Flower, 1931) and probably the 

 ass (47 years? — Flower MS.). Many larger mammals, including 

 baboons and other large primates, cats, bears, African elephant, 

 equines, tapirs, can approach or exceed 30 years (Chimpanzee, 



1 Those references marked 'Flower MS.' refer to the card-index of data 

 and letters from biological workers which Flower was preparing against a 

 revision of his first mammalian list, and which was uncompleted at his 

 death. This index is in the library of the Zoological Society of London, and 

 includes also bird and reptilian records and the skeleton of a list of inverte- 

 brate longevities. 



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