What does it take to become a dog/cat trainer?

Question

what classes how many years

Answer 1

Although in most cases animal trainers need to have a high school diploma or general equivalency diploma (GED) equivalent, some animal trainers must have a bachelor's degree and additional skills. Marine mammal trainers, for example, generally need a bachelor's degree in biology, marine biology, animal science, psychology, or a related field.

The Association of Pet Dog Trainers (APDT) is a professional organization of individual trainers who are committed to becoming better trainers through education.

http://www.apdt.com/about/default.aspx

It looks like you have to be a certified dog trainer schooled by a school qualified in the field.  Gain experience and then open your own business.  

http://www.schoolfordogtrainers.com/

There seems to be schools all over the place.  Google dog training career