LIFESPANS OF MAMMALIAN AND BIRD 

 POPULATIONS IN NATURE 



F. BOURLIERE 



Centre de Gerontologie Claude Bernard and 

 Ldboratoire de Physiologie, Faculte de Medecine, Paris 



The various marking and banding techniques devised by 

 mammalogists and ornithologists during the last 25 years 

 have provided us with a good many data on the maximum 

 lifespan of numerous species of mammals and birds belonging 

 to a large number of families of these two classes of verte- 

 brates. There are still too many gaps, especially for some 

 groups peculiar to certain geographical areas (such as tropical 

 species in general, small Australian marsupials), or for 

 families with specialized ecology (as cetaceans among mammals 

 and humming-birds or swifts among birds). Nevertheless we 

 already have a preliminary idea of the potential lifespan of 

 most families living in temperate countries. 



When we turn from individuals to populations, the situa- 

 tion is far less satisfactory. Very few species of mammals and 

 birds can indeed be aged accurately or have been marked in 

 sufficient numbers and followed long enough to provide us 

 with data which can be used to construct adequate life-tables 

 of natural populations. There are none the less a few figures 

 available and the purpose of this review is to bring together 

 this scattered information, bearing in mind that most of the 

 data at hand have been gathered haphazardly during eco- 

 logical studies made for other purposes and that none of them 

 are quite satisfactory from our present point of view. 



The more accurate observations we have for mammals con- 

 cern some of the larger ungulates which are of interest in game 

 management in Western Europe and North America. All 



90 



