of servicemen and women on the battlefield. we know this much about the dog that took part in the raid. it was in ft. campbell today and got the meet the president with the other s.e.a.l.s. >> reporter: just as the navy s.e.a.l.s who led the daring raid have gone unidentified, military officials also appear to be protecting the identity of the dog that helped them take bin laden. no name, no pictures, the pentagon won't even confirm it exists, leaving military analysts to just guess at what job the dog performed. >> i would imagine it would be used to detect explosive devices. >> reporter: dogs have been in the military for generations. in world war ii, all sides used dogs. the u.s. army had 10,000 for century duty, carrying messages and other critical jobs. today, there are only 2,700 at work in the military. but that number is rapidly growing and never before have they been in such specialized