Observations:
1. two different footprints; red and green.
2. The green footprints are larger than the red footprints
3. the green footprints were the only ones to walk away.
Logical Explanation:
The animal with the green and larger footprints comes in contact with a smaller animal with smaller footprints. The green footprints represent a primary animal, while red represent a secondary animal. The green footprint animal is the only one with footprints walking away because the primary animal, aka the bigger animal, ate the secondary animal.