A trunk is a complicated appendage. The tip is sensitive, working almost like fingers to help elephants eat. The flexible trunk shaft lets elephants shorten or lengthen their trunks and move them in all directions. But the unique makeup of an elephant's trunk is what gives him the amazing ability to smell water several miles away. His three nostrils breathe in the scent particles, which them pass through seven olfactory turbinals filled with millions of receptor cells. These sensitive cells differentiate between scents instantaneously, even from far away. For more powerful scent collection close-up, an elephant will touch something with the tip of his trunk, such as the urine of another elephant, and bring that into his mouth to pass it to his Jacobson's organ. This is a specialized organ in the top of his mouth that's attached to his nasal cavity, and it's used most often by male elephants trying to find a date.