I don't know; I know a lot of potheads who never progressed to heroin. BTW, earning a paycheck by getting rats stoned must be a real hoot.
3/4 of a joint for a baby rat?
The equivalent dose for a 170 lb. human would be - 2,000 joints with the estimated weight of the rat at one ounce!
Science - my @$$!
It says 3/4 of a joint "scaled down for a rat's size"