(CNN) -- You'll have to be doggedly clever to unlock Mike Linden's new iPhone 5S.

Linden, 23, was fooling around with the fingerprint sensor on the iPhone he purchased Friday morning. He found it dull locking and unlocking it with his own finger, so he decided to find out what would happen if he programmed the front right paw of his pet Chihuahua, Hurley, into the gadget.

Much to his surprise, the pawprint did the job.

Woof! Works for cats too.