Scientists believe that titanoboa was allowed to reach such a huge size because the place where it lived was much warmer than it is now. The body temperatures of reptiles like titanoboa depend on the temperature of their environment, and their bodies can only get so big before their metabolism slows down to the point where they basically can’t function. A snake that lives in a warm climate can grow large because the higher temperature supports its greater mass. This is a reason why the largest snakes in the world live around the Equator.