These are the most finely trained guard dogs on the planet, and the only thing more amazing than their array of skills is the price their owners pay for their protection.
In the city of Aiken, SC, is Harrison K-9 Security Services, which imports and trains German shepherds to obey commands with the discipline of a human soldier.
The dogs come from the purest breeding imaginable, according to CNBC. Some of them have bloodlines dating back 100 years.
They can understand English, German and a whole language of hand signals.
It's their combination of elegance, friendliness, intelligence and ferocity that has generated price tags ranging from $40,000 to $230,000.
The latter amount was paid for Julia, a German shepherd that protects a 15-acre estate just outside Minneapolis and another home in Arizona, The New York Times reported in 2011.
Julia's daily responsibilities include extensive cuddling, supervising children and looking beautiful.
Harrison K-9's vice president said Julia gets along remarkably with her horses and cats and is also a wonderful babysitter.
November Holley told the Times,
If my daughter Kailee was outside in the woods, I'd say, 'Julia, where's Kailee?', and she'd go out and find her. She was like a person.
But Julia is also a product of the same training as the dogs utilized by Navy SEAL Team 6, which raided the hideout of Osama bin Laden and shot him dead.
It takes just one word for her to instantly go from a cuddly pet to a ruthless guard dog.
A padded man entered the tennis court of Julia's Minnesota owner for a demonstration.
Johnson yelled "Packen!" (German for "seize") and, in the blink of an eye, Julia had sprinted across the yard to bite the intruder.
She only released her jaws when Johnson gave the command, but she kept her eyes on the intruder and bared her teeth whenever he moved again.
Harrison K-9 president Harrison Prather recalls a celebrity who once lived in fear of a stalker.
The stalker stabbed one of the bodyguards, got out of jail and started showing up again.
Then the celebrity, who is described as a famous entertainer, went to Harrison K-9.
The stalker saw the dog and has yet to return.