Rex served three deployments as a military working dog in Iraq for the US Marines. He was even the subject of a book written by his first handler in Iraq, Mike Dowling.
Just before Christmas, Rex died at the age of 11. He had already retired from active duty after being wounded during his last deployment. Rex had been adopted by his second handler, Megan Leavey.
Anchor Marco Werman finds out more about Rex's life, and about the lives of other military working dogs (or WMDs, as they're known) from Mike Dowling.