12 



A. Comfort 



more individuals reach old age than the early death rates 

 would lead us to expect (Haldane, 1953). 



It is evident that we can expect to obtain figures for most 

 of the long-lived animals only from existing records. These 

 include kennel and stud books, notes kept by laboratories or 

 by amateurs, and the record files of zoological gardens. The 

 material varies greatly in quality, and the statistical treatment 

 which it requires is different from that which serves for 

 laboratory or human actuarial work, since the data consist of 



x x 



WOLFHOUNDS 



SPANIELS 



DINGOES 



Fig. 2. Survival curve of 83 Irish wolfhounds by 

 yearly totals, sexes combined (continuous line). 

 Crosses ( x ) indicate ages of death of 14 spaniels 

 from the same kennel, and points ( • ) ages of death 

 of 15 dingoes in the London Zoo. 



multiple small samples, and in most cases there are substantial 

 losses from the record by sale, culling, or deliberate killing in 

 the course of experiments. 



We have been collecting material from sources of this kind. 

 It has so far been possible to construct survival curves for one 

 breed of dog, the Irish wolfhound (Comfort, 1957) and for 

 several animals (hybrid wolves, C. lupus lupus X C. I. 

 occidentalis ; dingoes; Ovis musimon, the mouflon; Ammotragus 

 lervia, the Barbary horned sheep; Dolichotis patagona, the 

 Magellan cavy; Boselaphus tragocamelus, the nilghaie; and 

 Muntiacus muntjac, the muntjak deer) from the records of the 



