The Defense Advanced Research Projects Agency calls it the LS3, for Legged Squad Support System. The robotic mule, dubbed "Big Dog", is under development at DARPA.

With the Big Dog prototype complete, Mandelbaum told Federal News Radio the next goal will be for the LS3 to operate for 24 hours, go at least 20 miles over very rugged terrain, carry 400 pounds, and do it all in a "quiet mode" if need be. As the meme (internet catch phrase) goes, "Your dog wants a steak."

The goal, eventually, is to field one LS3 for every 4 or 5 ground troops. That will be a big pack of dogs. "This could be as ubiquitous as a Jeep, if not more," said Mandelbaum, "especially in terrains such as Afghanistan where wheeled vehicles have difficulty over the very rugged terrain."

Which is exactly what the legs are for: to go where tracked or wheeled vehicles can't. Just like 2 and 4 legged animals, the LS3 can go over, and through, black ice, mud, sand, and water.

That's not to say it won't fall over. As Mandelbaum reminded, and Alex Karas proved in Blazing Saddles, "you can knock over a horse if you hit it hard enough." But the LS3 gets back up again, and keeps going.

While no one is trying to pass off the Big Dog as a horse or mule, future developments, said Mandelbaum, will probably reinforce the comparisons.

The LS3 vehicle will have a head. Big Dog vehicle does not have a head with sensors because it doesn't need it. It's controlled by a human, but the LS3 vehicle will be steering and controlling itself and navigating through the terrain so it will have a head with sensors on it. So it will look even more animal-like.

And like many faithful companions before it, the LS3 could draw fire and even provide temporary shelter in the heat of battle.

DARPA hopes to have Big Dog ready to join the hunt by 2014.