Other contributors have said "How old con a rattle snake get?" is the same question as "How old con a rattlesnake get?" If you believe that these are not asking the same thing and should be answered differently, click here
By the number of rattles on his tail and the size of the snake. You can not tell how old a rattlesnake is by the number or size of the rattle, you actually need tissue and blood samples to tell how...