
Actually, it's because beagles have higher cognitive abilities than rats/rodents that they do smoke.
Chimpanzees will smoke cigarettes voluntarily. :huh:
The higher one's cognitive abilities, the more addictive smoking is. Nicotine itself actually isn't highly addictive at all. There are monoamine oxidase inhibitors in tobacco smoke, among thousands of other horrid chemicals, and altogether, cigarette smoking enables the smoker to see the world through slightly rose-tinted glasses - that's why it's the poor and those with mental health difficulties smoke so much more than the rich and the well.
(Schizophrenia is a different kettle of fish - most smoke 80-100 fags a day - they are decidedly self-medicating, in a way not yet understood.)
(Ref. Informal lecture given by Prof. David Balfour just last April - he's a world authority in nicotine research.)