Very nice! I wouldn't be too fussy about the back legs since you're drawing is very much a cartoon style. I think it's lovely and with a drawing of this style you don't want to worry about getting everything perfect or it spoils the effect.
Just a quick comment on the side though, when you're drawing in pencil like this, drawing very lightly until you get to the exact shape you want, then you can go over a bit darker to do the outline. Otherwise you end up with liens across the paper where you've tried to rub out lines that were drawn in too dark ;)