Green and Red Vines in nature

The Green Vine Snake merges perfect in jungles due to its slender vine-like body form and green colour...Always wondered why would have a bright red, fork shaped tongue ??? Well then thought there might be 2 probable reasons- 
1. to attract prey 
2. vine or flora parts when young are often red or orange in colour, later fading. 
changing to their original colours
if the second is applicable, then the creator really must have taken a lot of time on details...

Small: A4: 11.69 X 8.27 inches
Medium: A3: 16.53 X 11.69 inches
Large: 2 X 3 feet : 24 X 36 inches