What factors lead to the differences in snake scales? Rattlesnakes seem to have a 'chunkier' armour look as opposed to the slick look of a python or boa. Thank you in advance for any information you can offer.

all traits/characteristics have evolved to allow that animal to best fit the niche it occupies. One can imaging that different scales might provide advantages in terms of climbing, protection from local terrain, speed of movement, heat transfer and attraction of a mate, to name but a few - I am sure there must be others. Don't forget the current environment as we observe It may not be what drove the evolution of those original characteristics.