A hot female who you spend time with/bang, but who is not your girlfriend. Woman has to be rated a "7" or above by 3 or more friends. If 3 or more friends do not rate your choice a "7" or above, she cannot be qualified as a Kangaroo Rat.
"have you seen my new kangaroo rat?"
"this is my new Kangaroo Rat"
Friends with benefits,
A girl you bang, but no relationship.
A girl you mess around with, with no attachments or responsibility.