The Distribution of Senescence 



least one 31 -year record was well supported. 33 years has been 

 claimed (Mellen, 1940). Figures for cats in England in recent 

 years included at least ten apparently authentic cases over 20, 

 and one gelt male alive at 28 (Comfort, 1955). 



Dogs very seldom exceed 18 years, and only exceptionally 

 reach twenty. In many breeds the limit is far lower. There are 

 remarkably few claims of greater longevity in the literature 

 (34 years, Lankester, 1870). 



Rodents: the rabbit can almost certainly exceed 15 years. 

 (10 years 3 months in the laboratory — Tegge 1936; buck 13 

 years — Barrett-Hamilton 1911; buck, chinchilla x Belgian hare, 

 11 years two cases; English buck 14 years, both authenticated 

 — Comfort 1955.) Flower MS. contains a plausible correspond- 

 ence with the owner of a rabbit (doe) which was said to have 

 exceeded 18 years and was still alive. 



2-2-2 BIRDS 



Flower's longest 'incontestable' record in captivity (Flower, 

 1925, 1938) was 68 years in Bubo bubo. This is probably too low. 

 Records exceeding 70 years in parrots, swans, and several large 

 predators given by Gurney (1899), though less fully proven, are 

 probably substantially correct. 



The maximum life-span in birds is not proportional to size. 

 It is materially longer than in mammals of comparable size and 

 activity. Many species can live 30-40 years, including small and 

 active birds such as pigeons (Flower 1938, Fitzinger 1853: 

 Streptopelia risoria 40 years, Columba livia 30 years, Goura cristata 

 (J 49, ? 53 years), while even the smaller passerines have a 

 potential life of 10-15 or more years in captivity (29 years in a 

 chaffinch — Moltoni, 1947) and ages of this order are occasion- 

 ally reached even in the wild state (Perry, R. 1953). It has been 

 properly remarked that 



A robin redbreast in a cage 

 Lives to a tremendous age. 



Extensive aviary records are given by Chalmers Mitchell (1911). 



49 



