Watch A Forensic Scent Dog Track Down A Hidden Pen

January 12, 2026

A dog named Saul is showing the world just how powerful a canine nose can be.

In the remarkable video, a man writes on his hand with a pen and then lets his dog, Saul, smell the ink. Moments later, the pen is tossed into a field of tall grass, completely out of sight.

Using nothing but his nose, Saul charges into the field and tracks it down, locating the pen with astonishing accuracy.

The clip is more than just a cool trick — it’s actually part of Saul’s real-world training. According to his owner, Saul is being trained as a detection K-9 for a medical condition listed in his bio profile. To do that job properly, he must be able to detect extremely tiny amounts of specific volatile organic compounds (VOCs), which exist at “micro-gas” levels in the air.

That’s where the ink comes in. Ink gives off microscopic scent particles, making it a perfect tool for teaching Saul to lock onto incredibly faint odors. By tracking something as small as ink residue, Saul is building the skills needed to detect even subtler chemical signals tied to health conditions.

There’s another powerful reason for this kind of training, too. Saul is also being taught to find personal items someone may have dropped if they are lost in a dangerous or hard-to-reach environment. If a missing person leaves behind a handwritten note or piece of paper, Saul’s ability to detect ink could help lead rescuers straight to it.