This snake can grow to a maximum total length ( body + tail ) of 166 cm ( 5.5 ft ) and averages about 120 cm ( 4 ft ) on mainland Asian populations , although island populations do not attain this size .
Russell 's Vipers can grow up to the length of 166 centimeters ( 5.5 ft ) , but they are usually around the length of 120 centimeters ( 4 ft ) .