From the use of war dogs and horses by the Romans to Hannibal's elephants to modern naval programs involving dolphins and beluga whales, animals have long played a role in mankind's feuds.
In the quest to conquer the enemy, humans have looked to Mother Nature for help and inspiration for thousands of years. And today is no different.
"Animals have been part of military operations since there have been military operations," said Noah Shachtman of DefenseTech.org. "They have been the fighting man's best friend for generations and in modern-day warfare that's still the case."
Mother Nature as Muse
When researchers at the Defense Advanced Research Projects Agency look for innovations to keep the U.S. military at the top of the technology heap, they need only look out their windows.
"Over the centuries, biological systems have evolved unique capabilities to find a mate, find food, basically the things they need to do to sustain life," said Jan Walker, spokeswoman for DARPA.
Walker said that the beings that walk, crawl, fly and swim across our planet have developed ways to survive and to accomplish tasks, and we can learn from them.
"In some cases, biological systems have developed unique abilities," she said. "There's a beetle whose life cycle includes laying eggs in the bark of a burned tree. It has the ability to sense a forest fire from huge distances away so that it can get there to lay its eggs, and we want to know, how do they do that?"
Though it may sound like science fiction, DARPA at one point sponsored research to understand more about how sharks detect things that don't belong in the water.
"Sharks have a unique ability to track chemical plumes in the water," she explained. "We sponsored research that studied that ability, and so we implanted electrodes so that we could learn what part of the brain was active as the animal sensed the plume."
DARPA doesn't talk too much about applications, but the idea of remote-controlled shark spies was widely reported as one possible application.
More recently, the agency began to solicit ideas for how to use insects as bomb sniffers, possibly by introducing a microchip into the organism while it's still in the pupa stage.
But DARPA makes it clear that it doesn't develop these things on its own; it comes up with ideas and seemingly unanswerable problems and lets others figure out how to solve them.
That's led to all kinds of innovations that build on what nature has already achieved.
"There's been a big push to try to learn from the lessons of the natural world and adapt them to robotics," explained Shachtman.
Now a Navy research project, the Biomimetic Underwater Robot, Robolobster, is ... well, a robotic lobster that moves just like its organic cousin.
It's "basically a mechanical lobster that scurries along the ocean floor and looks for mines and buried bombs and stuff like that," Shachtman said.
According to the Web site for the Office of Naval Research, "Biomimetic robots are, in principle, relatively small, agile and relatively cheap, relying on electronic nervous systems, sensors and novel actuators. Most important, they can take advantage of capabilities proven in animals for dealing with real-world environments."
No one from the ONR was available for comment.
Walker said nature has done all the work and figured out that the lobster's design is perfect for operating in heavy surf.
"The lobster is able to maneuver inside the surf zone where the water is very rough," she said. "We want to know, 'How does it do that and keep from being knocked around?'"
Biggest Dog on the Block
A U.S. soldier in the field can be weighed down with 100 pounds of gear or more. The sheer exhaustion associated with carrying that kind of load -- particularly in the deserts of Iraq -- can affect his ability to do his job, whether it's fighting alongside his comrades or supporting them.
Leave it to DARPA to come up with a unique solution to that problem, too.
"'Big Dog,' which is by a company called Boston Dynamics, is not actually a dog, it's more like a pack mule," said Shachtman. "The idea is to offload some of that weight onto this robotic pack mule, and this thing actually walks."
The four-legged robot can traverse rough terrains, trotting alongside soldiers with the heavy gear that once weighed it down.
Though still being developed, "Big Dog" is a great example of learning lessons from nature, sprinkling in a bit of technology and solving a problem that plagues the military.
You're Under Arrest -- Dolphin Style!
The U.S. Navy Marine Mammal Program has taken more than a few shots from animal rights groups over the years for its use of dolphins and sea lions in military operations.
Though the Navy admits it uses the animals' exceptional internal sonar to track mines and even identify enemy divers, it denies they've ever been used in offensive operations.
Still, rumors persist that dolphins have been equipped with weapons and Shachtman said he has heard tales of the friendly-looking mammals making aquatic arrests.
"Dolphins are used both as mine watchers and in some cases to intercept and handcuff enemy swimmers," he explained. "They sort of go down with a set of cuffs in their teeth, and they can manipulate them and get them on."
'All Kinds of Kooky Projects'
While there are no sharks yet in uniform and cyborg insects are still in development, Shachtman finds some encouragement in the military's more unusual programs.
"The Defense Department is what, $600 billion a year?" he asked. "That leaves a lot of room for all kinds of kooky projects. I wouldn't say there's an order from Donald Rumsfeld to build mechanical bees or something like that, but especially in DARPA, there's a desire to explore and freedom to look into things that may or may not work out militarily."
He believes that, although many of DARPA's programs are scrapped before they're seen through, it's one of the few places in government research where dreaming is considered an asset.
"I wouldn't interpret that to mean we're going to have an army of dolphins and robotic bears attacking the enemy anytime soon," Shachtman joked.