George H.W. Bush's Service Dog Sully Guards His Coffin in D.C. [PHOTOS]

This touching photo of George H.W. Bush's service dog lying by his casket is proof that dogs really are man's best friend.

The trained labrador went to work with Bush this summer after former first lady Barbara Bush passed away earlier this year.

According to CNN, Sully is named after "former airline pilot Chesley B. "Sully" Sullenberger III, who became famous for landing a damaged passenger jet on the Hudson River and saving all 155 passengers and crew in 2009."

Sully can perform a two-page list of commands, including answering the phone and fetching items, his new assignment will be helping veterans at "Walter Reed National Military Medical Center."

Check out some of his adorable pictures with his boss.