By Verity Murphy
BBC News Online
With the military build-up in the Persian Gulf showing no sign of abating the US Navy has unveiled its secret weapon - a crack troupe of sea lions.
The specially trained mammals have been deployed to the region to protect US and British warships against attacks from underwater saboteurs and mines.
The sea lions can carry out repeated dives to great depths without tiring
These whiskered warriors are even capable of clamping a floating marker to the legs of an intruder, alerting troops to his position, who can then move in and haul the attacker out of the water.
The British naval commander in the Gulf, Rear Admiral David Snelson, warned on Monday that possible al-Qaeda attacks on warships in the region was the biggest security threat facing his forces as they prepare for a possible war with Iraq.
Three years ago 17 US servicemen were killed when the USS Cole was attacked in the Yemeni port of Aden by al-Qaeda operatives using an inflatable boat packed with explosives.
They never enlisted, they know nothing of Iraq or Saddam Hussein and will probably not survive
Now as an armada of more than 130 US and British Navy warships and support vessels is crowded into the Gulf, the sea lions have been pressed into action.
Sea lions were chosen for the task of patrolling the harbours because not only are they extremely intelligent, but they have acute directional underwater hearing and work well in low light visibility.
"They have very sophisticated sonar systems that can detect movement," said Rear Admiral Snelson.
In addition they can swim at 40 kilometres per hour (25 miles per hour) and carry out repeated dives of up to 300 metres (1000 feet).
"For thousands of years of his history, man has made use of the capabilities of animals, their strength, extraordinary senses, swimming or flying ability," Tom LaPuzza, public affairs spokesman for the US Navy Marine Mammal Programme said.
But animal rights groups object to the use of animals in combat.
Among those carrying out patrol duties will be 385-pound Zac
"It is simply not ethical to put animals in harm's way. War is a human endeavour and while people and political parties may decide war is necessary, animals cannot," Dawn Carr, a spokeswoman for People for the Ethical Treatment of Animals (Peta) told BBC News Online.
"They never enlisted, they know nothing of Iraq or Saddam Hussein and will probably not survive," she added.
The US Navy says it has about 20 of these sea lions, who can be rapidly deployed by land, sea or air.
They regularly take part in major naval exercises, but this will be the first time they have taken on a real combat role.
The sea lions in the Gulf are all graduates of the US Navy's Marine Mammal Programme in San Diego, California.
There they are trained in mine recovery - diving down, locating a mine and if possible attaching a grabber device which can be used to recover it.
The US Navy has used dolphins in combat roles since Vietnam
They also learn how to alert humans when they detect an intruding diver and even attach a restraint device - a c-shaped clamp which locks onto the diver's leg like a handcuff - before deploying a floating buoy attached to the cuff and swimming away to safety.
Sea lions can even pursue a suspect onto dry land - alerting all in the vicinity with their loud honks.
Also based in San Diego are three groups of dolphins, also trained to detect mines and humans.
Dolphins are no strangers to combat, having been used by the US Navy to patrol the water of Vietnam during the 1970s as well as the Persian Gulf in the Iran-Iraq war.
But this time the Navy opted to use sea lions because they are more manoeuvrable than their cetacean counterparts and better able to handle the higher temperatures in the region.
Since the days of Hannibal crossing the Alps with his elephants an exotic array of animals have been pressed into military action.
Even bats have been called upon to take part in military attacks
Perhaps the most bizarre plan was when the US launched Project X-Ray in World War II - an attempt to attack Japan with bats carrying tiny satchels bearing incendiary devices.
The plan backfired when on a practice run the bats attacked the wrong target, and set fire to a military airfield in New Mexico.
In the recent Afghan conflict troops were on alert for attacks by kamikaze camels strapped with explosives, a tactic the mujahideen used against Soviet troops.
And in the event of a US-led attack on Iraq the US army plans to ride chickens into battle in cages atop Humvees, used as early warning gas detectors.
The US Army calls the strategy Operation Kuwaiti Field Chicken - or KFC - but the plan has been put on hold after 41 of the 43 chickens deployed to the Gulf died within a week of arrival.
Still, headed into the fray will be some of the 1,400 dogs who work in the US military - carrying out tasks ranging from mine detection to the rescue and recovery of dead and wounded personnel.