As the daughter of a veternarian that practiced for 50 years, I have seen more of my share of problems with dog fights, attacks on other pets, even humans, etc. It can be a behavioral problem, learned behavior, overly protective of property or their owner, lack of responsible ownership, a health problem, or the way the dog was raised from a puppy. Personally, I believe a lot of it is related to responsible pet ownership and training.
This doesn't only happen in Belize or the states...years ago, my girlfriend and I headed down to Cabo to relax for a few days in the Mexican sun. While walking from our condo to a restaurant, we were surrounded by a pack of dogs (small and large, different breeds), they seemed to appear out of nowhere and very suddenly. My friend began to panic...the last thing you should do. I instructed her to get up on the wall bordering the walkway and keep eye contact. It was terrifying for a few minutes, but gradually, they trotted off.....I am very wary of strange dogs running loose...ever since.