Generaly 6-8ft and weigh 15-supposedly 40 lbs. I have never seen and actually scale read 40 lbs. But anyway. You can generally get ones with good tempermants. Most of my boas have never struck at me or biten me. As adults they can be fed jumbo rats every 2 weeks. Some people do rabbits, but that isn't neccesary. A female 8 ft boa could easily eat a small dog. But that can be averted by keeping a secure cage and not letting the dog in the vicinity of the snake while it is out of its cage. Read a really funny story one day about a boa constricting a nun's dog that a guy that kept snakes was puppysitting. The dog turned out fine that is why it is funny. It is very irresponsible though.