The chihuahua is the smallest breed of dog in the world. Its homeland is Mexico. In the ratio to the body size chihuahua has the biggest brain among dogs. They easily give in to training and learn quickly new commands. Despite their tiny size, these dogs can be very aggressive that's why they must be accustomed to "society" since their childhood. For the first time a chihuahua appeared in Russia in 1959 when Fidel Castro presented two puppies of this breed to Khrushchev as a sign of friendship.