Methods of Marking Reptiles for Identification after Recapture

Abstract

WHEN studying, in the summer of 1939, a mid-Swedish population of the grass-snake, Natrix n. natrix (L.), we considered it necessary to work out some method of identifying each individual snake from year to year, making it possible to follow its changes in colour and size, etc., with increasing age, the appearance and subsidence of sicknesses, the healing of wounds, the sexual cycle, and movements within the territory inhabited by the population. The movements of individuals could not be studied in any other way; and the morphological changes with age were otherwise determinable merely as a result of statistical population studies, which could only be rough approximations, the individual variation in growth being far too great for it to be possible to distinguish the higher age-classes even with plentiful material.