Dangerous Hunts 2009

Or, if you are having trouble finding snakes, like I was...Start the mission, kill they hyenas, after the tigers escape, go to the Temple fist, Tranq the tiger and kill the 5 snakes in the temple, rinse and repeat two more times...once you have killed your 15th snake, finish the mission and it will pop. :)

This achievement is quite easy. During the career mode, you will be directed to complete missions, and during your travels, you will encounter poisonous snakes in your path. I managed to get 15 during the 3rd or 4th level without even trying to. Make sure to use Hunter Sense (Left Click) to help spot 'em.