Washington - Chickens, dogs and dolphins have been given their marching orders to help protect United States troops in Iraq.
Chickens defy death in cages atop American military Humvees to detect a possible Iraqi chemical attack.
Well, some don't exactly defy death. Most expired after a short stint in the Iraqi desert - flu is suspected - and pigeons have taken their place.
Dogs - long used in warfare for scouting, relaying messages and rescuing injured soldiers - are sniffing out bombs in Iraq.
And dolphins Makai and Tacoma are helping to clear mines.
Warfare has long depended on the feathered and the four-legged, whether they were elephants bearing javelin-throwers on the battlefields of the ancient world, camels spooking Byzantine cavalry horses with their pungent smell, or Spanish conquerers' mastiffs hunting down Peruvian Indians.
"Without animals, historically, war as we know it would have been flat-out impossible," says Dennis Showalter, history professor at Colorado College.
"If human beings had to carry the weight of food they ate, munitions they use, on their own backs and feet, we might have stayed closer to our homes."
Coalition forces brought in the two bottle-nosed Atlantic dolphins to detect sea mines in the British-controlled Iraqi port of Umm Qasr -something they are trained to do without setting off the explosives.
"Now we have humans, machines and animals working together to clear the mines in Iraqi waters," said Tom LaPuzza, spokesperson for the Navy's marine mammal programme in San Diego.
LaPuzza calls dolphins' ability to detect things at a long distance "the best show in town".
Sea lions have also been sent to the Persian Gulf and are being tested to see whether they can capture an enemy diver poised to attack a ship or pier.
Bearing a clamp inside their mouths, the swift creatures approach a swimmer from behind and attach the clamp - connected to a rope - to his leg. Sailors aboard ships can then haul the swimmer out of the water.
The sea lions can also be used to recover military hardware or weaponry in the ocean.
Marines of the Seventh Regiment brought in pigeons to take over from the 42 chickens that died.
If the birds get sick, that could signal a chemical attack, giving Marines some time to don gas masks - a role once played by canaries in coal mines.
Animal rights activists say creatures don't belong on the battlefield.
"Making these birds participate in our wars is not only cruel and unjust, it is a betrayal of the men and women who are serving under you," Machipongo, Virginia-based United Poultry Concerns said in a letter to President George Bush.
The group said that many of the chickens will die of hunger, thirst and oxygen deficiency while being driven across a desert, and that there are better ways to do the job - with sophisticated chemical detection systems.
Showalter agrees, but makes a case for the chicken as placebo.
"They help people feel better because a chicken is alive and we will trust a living thing's reaction to gas before something mechanical," he said
Dogs have served in the US military during every modern war from World War 1 to the recent conflict in Afghanistan, as trackers, scouts, sentries, messengers, attackers, mine detectors and rescuers.
The Vietnam Dog Handlers Association has proposed a National War Dog Memorial for Washington. About 4 000 war dogs served US armed forces during the Vietnam war, according to the group.
Horses were considered the supreme war animal from the end of the Bronze Age through the 19th century, and they still have a place in battle.
In the Afghan war, US-backed rebels galloped against the Taliban, sometimes joined on steeds by American soldiers, half a century after the US dissolved its last mounted fighting unit.
Horses have proved a handy way to move fighters and supplies in Afghanistan's rugged terrain.