Thanks for the replies and the info. I started to find american bulldogs breeders in puerto rico, cause i think that the american bulldog is the more appropiate to the warm climate of pr. I have been searching and the bullmastiff here in pr cost around $1,500 to 2,000. that is a lot of money. The other dog that i like was the dogue de bordeaux, but didn't like the ones that i saw here, they were from show lines and their life expectancy was 4-5 years. Other recomendations were the dogo argentino and the rhodesian ridgeback, but need a hell lot of space and were too drivey. And the presa canario, but too much of a temperament and the owner of ten here in pr was attacked by one, and went to hospital 3 months. When a presa attack, it is very difficult to stop them. Beautiful dogs , but for persons with lot of space. The other day i was reading a book titled k-9 bodyguards, the man that write it lives in florida, a very similar climate to puerto rico. He recommended the american bulldog, maybe because is an american and affordable breed, but also the breed is very healthy and intelligent and secure. So i think that a well bred american bulldog is a good solution. I don't know too much about the lines, cause every dog that i see is from johnson lines, so if someone can give me more info about the strains, welcome.