Border collies are real bundles of energy, and love all mental and physical challenges. They often complete tasks quicker than their masters can come up with new ones for them to do. They can even learn to wind down car windows, jump a skipping rope or balance glasses of water on their nose. It's no wonder that they regularly win the awards at agility and retrieving competitions. In addition, border collies can understand up to 1,000 words – far more than a two-year-old child.