CHAPTER X 

 HABITS 



SNAKES may be grouped, according to their 

 mode of life, in five principal categories, 

 gradually merging into each other, or two of them 

 not infrequently found combined in one and the 

 same species. These categories are : — Ground-snakes, 

 Sand-snakes, Burrovving-snakes, Tree- snakes, and 

 Water-snakes. 



Ground-snakes may be defined as living above 

 ground, and only occasionally climbing bushes or 

 entering the water. Among European genera, 

 Coronella and Vipera are perfect examples of this 

 type, whilst Coluber and Zamenis approach the 

 Tree-snakes in often ascending bushes, or even 

 trees. 



Sand-snakes are adapted for living on loose 

 sand, in which they seek concealment. Such are 

 Lytorhynchus and some Psammophis among the 

 Colubridse, Cerastes among the Viperidse. Eryx con- 

 nects this category with the next. 



Burrowing-snakes live chiefly underground, and 

 often have the visual organ atrophied in consequence, 

 as in Typhlops ; all the Typhlopidae, Glauconiidae, 



9i 



