Spanish group of veterinarians from the University of Barcelona was investigating the cases of dog aggression? All investigated cases have happened in in Spain from 1998 to 2007, as a result, there was named the most aggressive breed.

According to the experts, the most generally unbalanced breeds are: Rottweilers, Boxers, English Cocker Spaniels, Yorkshire Terriers and (surprisingly) German Shepherds. However, the English Cocker Spaniels were recognized as the most aggressive dogs.

"At least in our country, this hunting breed shows a high level of aggression", - says the head of researchers - Martha Amat.

The researchers had analyzed 1040 cases of dog aggression, which were reported by the owners of those dogs. It turned out that the English Cocker Spaniel is more likely to attack people (both: their own masters, and the strangers). At the same time, other breeds of dogs usually show aggression only toward other dogs.

In addition, the Spanish veterinarians found another consistent pattern: it turned out, that among all the English Cocker Spaniels the most aggressive reactions were shown by the males of a red color.

Martha Amat said that such a connection with the color is due to the fact that the level of melanin, which determines the hair color, corresponds to the production of dopamine, as well as many other chemicals that influence the aggressiveness in dogs.

Another group of researchers - from the University of Cordoba, was comparing males and females of the English Cocker Spaniels of red, black and mixed colors. In the course of their investigation, this hypothesis was confirmed, but the scientists also noted that in more than 40% of the cases the resposibility for the Cocker Spaniels aggression is on the owners who are not able to provide the sufficient obedience of their dogs.