How is a bearded dragon measured? some say from the tip of the nose to the tip if the tail. Then some say from the tip of the nose to the tail base. Which is correct?
The proper measurement of a lizard's size is "snout to vent length" (SVL). The measurement is taken taken from the tip of an animal’s nose to the opening of the cloaca at the tail's base.
Measuring the entire length (including the tail) has no biological meaning and can be somewhat deceptive about what it means. The length of a tail varies so greatly, it has little correlation with age, size, health, or whatever other biological factors you might be trying to determine from a reptile's overall length. Reporting the entire nose-to-tail length is typically reported to exaggerate the actual size of the animal (as in "a ten-foot alligator was found in the neighbor's pool")… but beyond that, such measurements have little biological value.