Dog is truly man's best friend and this video teaches you that lesson exactly. Jon T. Tumilson was a Navy Seal U.S. Petty Officer 1st class who was killed in action by Taliban Insurgent's attack on a helicopter.

The attack claimed the lives of 30 American troops. His dog Hawkeye sat by his coffin during the service in true mourning for his fallen friend.

[Source: Animal Planet]