Dog nails are constantly growing, just like human nails. Some dogs wear down their nails naturally from walking on pavement, gravel or concrete. However, the majority of today's dogs live indoors and don't spend enough time on these surfaces to keep the nails short. This is especially the case with small dogs (like Chihuahuas and Miniature Dachshunds - two breeds that seem to especially dislike having their paws touched). If left to grow, some dog's nails will curl under and actually start growing into the foot pads. This leads to painful sores and infections. Even if they do not curl under, long nails can make it difficult for dogs to walk, especially on slick surfaces. Finally, long nails can easily get caught on something and become partially torn off or split. This is very painful for your dog, and treating a torn nail may require sedation at your vet's office.