Most Hebrew speakers if asked, would tell you that Rachel is a baby Sheep (lamb). However what does Leah actually mean? Some sources explain that Leah actually means a cow - either from Arabic or from the ancient Akkadian.
So basically the two daughters of Lavan were named a Cow and and a Lamb..very fitting for a Shepard. Weirdly not one of the tribes has a name that is connected to the family profession.
Note: I remember that Da'at Mikrah has a similar explanation, but not owning a copy, I couldn't check my memory. Kasuto explains that Le'ah is named after a word for a deer..