It's a sad fact, but shelters nationwide have no choice but to make an educated guess when it comes to the age of the dogs in their care. Approximate age in years is possible, but as to the date of birth — their true birthday — it's just not possible. So to give these wonderful dogs their much deserved recognition, North Shore Animal League America has declared the first day of August as DOGust 1st®, the designated birthday for all shelter and rescue dogs — or as we like to call them, Mutt-i-grees.