Eighteen years in the military have been truly a dog's life for Air Force M. Sgt. Thomas Edward Hawkinson. Hawkinson, 38, and known as "Hawk" to his human buddies, is in charge of the Department of Defense's 700-acre Dog Center at the Lackland Air Force Base in San Antonio, Texas. A Harvard for hounds, the center's four-legged alumni make up the elite 2,400 "Working Dog" corps that patrol, among other significant spots, the White House, nuclear power plants, airports, military bases, planes and ships. There they guard against, among other threats, intruders, bombs, bugs and drugs.

Before earning their dog tags, Hawkinson's charges must pass a rigorous six-week basic training program. As operations branch chief for the $3 million program, he is responsible this year for locating and educating 1,001 dogs of various breeds. To find them, Hawkinson tests at least twice that number after looking over thousands more during cross-country canine-recruiting tours.

"We want them mild-mannered and hard-biting," Hawkinson says of his enlistees. Other requirements: Most dogs should be between the ages of 1 and 4, weigh at least 50 pounds, measure 21 or more inches across the withers and be in top physical condition. German shepherds are by far top dog on the force, representing 88 percent. Hawkinson ranks them highest in all-around ability. What's more, a shepherd's bite is worse than its bark: It can dig in with 750 pounds of pressure.

The dogs in Hawkinson's training come entirely from owners who can't or don't want to keep their pets, since he wants dogs who are accustomed to people. He rules out both mutts (Hawkinson says they don't have the necessary attention span—sorry, mutto-philes) and dogs raised professionally. When Hawkinson likes the looks of a dog, it is put through physical and psychological testing to see if it's qualified to enroll in the $8,000-per-dog program. If so, it begins training, during which it is taught the rudiments of good dog manners (sit, heel, play dead, etc.), the correct responses to a minimum of 135 commands, and to race through an obstacle course complete with walls, barrels and catwalks. "A good dog has the intelligence of about a 6-year-old child," Hawkinson claims.

After a dog completes basic, it goes on to specialized training geared to the job it will fill. All but 200 of the dogs currently in the program are assigned to the military. (The others are assigned to federal agencies for such jobs as sniffing luggage in airports, where they have detected nine bombs so far.) They are taught what Hawkinson calls "controlled aggression." He says dogs used to be trained to "bite, bite, bite," but now are taught to bite, hold and release on command. Military dogs are also trained to sniff out narcotics and explosives (a dog's sense of smell is 40 times more sensitive than a human's) and watch for intruders (they are extraordinarily sensitive to movement at great distances and hear 20 times better than people). They are, however, washouts at map reading (dogs are color-blind).

Despite the prevalence of shepherds, a smattering of other breeds have won favor with Hawkinson. These include terriers and beagles, who can squeeze between pipes and tubing on ships and planes, and retrievers, who proved in Vietnam that they can muck through the boggiest of swamps to locate and remove smaller bombs.

Some breeds with a reputation for being mean are strictly 4-F with Hawkinson. He says Rhodesian Ridgebacks, large dogs originally bred to chase down lions, "just won't bite a man." The same holds true for Great Danes, whom he dubs "the biggest babies that ever lived," while Dobermans he finds lacking in nerve and basically wacko. He cautions big-dog owners, however, that even though their pets can't be reliably trained to chomp on command, they may still bite humans when defending their territory.

Hawkinson began dogging it almost as soon as he joined the Air Force as a 20-year-old. The son of a shipping agent, he was born in Natchez and grew up in Mobile, where he often preferred his cocker spaniel to the neighborhood kids. While taking a routine bus tour of the Lackland base as a recruit, he spotted the rows upon rows of dog-filled kennels, signed on immediately as a dog handler, and has never bowed out. He met his Korean-born wife, Haeng Suk, 26, while on a dog-teaching assignment overseas in 1977.

At 6'2" and 220 pounds, Hawkinson is big enough to intimidate his charges if necessary, but he's a veritable softie. Soft-spoken and well-educated (he has an M.A. in criminal justice from Webster College in St. Louis and is about to start on a Ph.D.), he never yells at or punishes his troops. Dogs are encouraged with kind words and strokes from their 35 handlers; upon completion of a task, they are either given a treat or allowed to play with a rubber ball. If the dog blows an assignment, he is allowed to try, try and try again until he succeeds. "Everything is structured to make certain that the dog never loses in any sort of confrontation," says the master sergeant. "It builds their confidence to the point where they will take on anything their handler commands them to." (Noncanine recruits take note.)

Oddly enough, Hawkinson doesn't own a dog, though he is shopping for a shelty, a sort of miniature collie, for his daughter, Loria, 4. Whether he can train it to bring his slippers and stay on the sidewalk remains to be seen.