Move over pony express. Turns out there was something of a dog express in 1886 when a small dog named Owney was adopted by the Albany, New York post office and soon began escorting vast shipments of mail on cross-country trains. Today, the United States Postal Service honors Owney with a special edition stamp featuring his picture and the make-shift postmarks he received everywhere he went.
http://www.huffingtonpost.com/kate-kelly/owney-post-office-dog_b_909303.html
