12 



Colouration, 



Colour 



changes 



occuring 



after death 



in the 



Dendrophis 



Pictus. 



Surface 

 Colouration. 



The Colouration of snakes is of three kinds : 

 (i) The natural colour of the scales. 



(2) Colour formed by pigments under the 

 skin. 



(3) Colour on the skin between the scales. 



Most dull-coloured snakes, such as the Cobra 

 and Rat-snake, belong to the first class. 



The second form of colouration is found 

 mostly in Tree and brightly coloured snakes, often 

 together with the third form of skin colouration 

 between the scales. 



It is the colouration by pigments that is 

 responsible for the colour change which sometimes 

 occurs in certain snakes. The skins of snakes 

 coloured in this way lose their colour after the 

 snake has been killed and the skin removed. 



Take, for example, the Dendrophis Pictus- 

 The colours found on this snake when alive are 

 very numerous, and comprise blue, green, brown, 

 olive, and yellow. 



After death the pigment (or optical) colours 

 disappear, leaving the scale colouring, brown and 

 olive, and the sky blue colour found on the 

 interstitial skin. These fade, and the ground colour, 

 when the skin is dry, is dark blue, fading into light 

 blue near the ventrals, though, when held to the 

 light the part originally coloured by pigment is 

 found to be transparent, and is crossed by dark 

 streaks, which are what remains of the colour on 

 the interstitial skin. 



Scale colouration is not always uniform, but 

 certain scales may be of a contrasting colour, and 

 form a pattern. The depth of the colour in a 

 snake's skin may be judged by the fact that the 

 cast epidermis of a snake is colourless, though in 

 the case of the Python dark marking may be 

 faintly seen on its cast skin. 



