Quick tutorial to show you how to draw animated footprints in vector.
1) Select the Pencil tool and draw the inside of the paw.
2) Select the Ellipse tool and draw the toes of the paw.
Your Footprint should now be complete, mine looks like this:

3) Group the shapes as a shape
4) Group the shape as a sprite
5) Open the sprite and cover the parts of the footprint with the Ellipse tool, like this:

6) Group all masks together in a sprite and place it under the shape
7) Open the mask sprite and select all the shapes in it
8) Align them to center and set te width and height to 0.1%
9) Add a move effect for all shapes (for example 10 frames) and at the end of the move effect set the width and height to 100%
10) Tick the 'stop playing at end of sprite' for the mask sprite and tick both 'stop playing at end of sprite' and 'use bottom object as mask' for the 1st sprite.
11) copy the first sprite and paste where new footprints should be visible.
12) Add place effects on the main timeline for the sprites.
Done!
You can find a finished example in our downloads database here:
clickGood luck