Only the cool ones

  > "Mice smoke?"

The experiment summary:

  > "The team bred four strains of mice.
  >  They then exposed the mice to a single dose of the liver carcinogen diethylnitrosamine (DEN).
  >  DEN is found in tobacco smoke."

They simulated the "consequences" of smoking in mice.

When near the lab's Bunsen burner.

Only if they grew up near a BBQ joint