Everyone knows security dogs. Now meet security sea lions.

With Iran threatening to prevent passage through the Strait of Hormuz, the U.S. may face the threat of waterways congested with mines. But Mother Nature has a solution.

“Mammal systems” such as dolphins and sea lions have supported the U.S. Navy for more than 40 years. They were useful during the Vietnam War and Operation Iraqi Freedom, and they have engaged in counter-terrorist missions.

The U.S. Navy’s Explosives Ordinance Disposal team locates, identifies and disposes of mines from 30,000 feet in the air to 300 feet below the sea. It considers sea lions and dolphins superior to UUVs (underwater unmanned vehicles) for some of those missions.

Dolphin mine hunters cleared the entrance, waters and harbor of Umm Qasr, Iraq, to support the humanitarian aid mission in the Spring of 2003. Now they may have to perform a similar role if supply routes need to be cleared in the Strait of Hormuz.

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The Navy trains and deploys two species: the bottlenose dolphin (Tursiops truncatus) and the California sea lion (Zalophus californianus), both of which are known for being robust, trainable and adaptive -- solid selections to help defend the nation.

Just as dogs can detect bombs with their exceptional sense of smell, dolphins can locate objects in the water with their natural sonar, useful where hardware sonar performs poorly due to acoustic conditions.

Dolphins are therefore deployed on “swimmer defense,” meaning they detect enemy divers, swimmers and swimmer delivery vehicles.

The second half of this dynamic duo, the sea lion, brings its skills at detecting, marking and retrieving objects, thanks to its underwater directional hearing and strong low-light vision -- which means it can help nab enemy divers.  It also can get through tight spaces quickly and get onto shore if the need arises.

It can take a sea lion less than a minute to locate a mine embedded in a pier. When detected, it reports back and the Navy divers are deployed for further action.

Ordinarily, recovering unarmed test ordnance is complex and dangerous: Human divers must contend with poor visibility, currents and limited windows of time. They also require surface support, a recompression chamber and medical personnel.

But it takes just one sea lion, two handlers and a simple rubber boat to conduct the same recovery to a depth of 1,000 feet, well beyond the standard 650 feet.

The sea lion signals if it hears an ordnance beacon and swims down and attaches a retrieval device connected to a line. A crane retrieves the object, and the sea lion is rewarded with a seafood dinner.

Trained to locate enemy swimmers or divers lurking near piers or anchored ships, sea lions also regularly support human security personnel.

Their speed -- they can swim 25 miles per hour and run as fast as most humans -- lets them move in to help apprehend an enemy diver.

Not only can they locate and recognize different shapes of mines, they have been trained to attach a leg cuff -- the sea version of handcuffs -- around a diver’s thigh. The cuffs are attached to a line so their handlers can reel in a saboteur for questioning.

Sea lions patrol in a special video-equipped harness that gives sailors a live, real-time window on underwater threats. Both dolphins and sea lions move so much more quickly and accurately in water than humans that the animals are typically in and out without the bad guys knowing they were there.

The sea mines that dolphins locate and mark are designed to be triggered by large vessels, not by passing animals, so the mammals are at low risk. They never carry live mines, and their handlers clear them out while Navy technicians tackle the challenge.

Over short distances they are trained either to swim alongside a small boat or to ride in the boat itself. For remote deployments, when they are transported in large naval vessels or by planes or helicopters, they get custom designed enclosures that are comfy -- wet and cool.

Dolphins, for example, are given fleece-lined stretchers suspended in fiberglass aquariums, and they are escorted and monitored by a veterinarian and handler. Upon arrival, they get state-of-the-art facilities.

For several decades, the program’s true mine-hunting and swimming defense missions were classified -- triggering speculation that the dolphins were being abused. Declassification in the early ’90s meant the military could finally refute allegations that they were being deployed as offensive weapons.

Offensive deployment wouldn’t make sense anyhow, since the animals can’t distinguish between friendly and unfriendly vessels, swimmers and divers.

Marine mammals have so much potential that the Navy created the Navy Marine Mammal Program (NMMP), focused on studying, training, and deploying them from a facility in San Diego.

For Project Deep Ops, two killer whales and a pilot joined the team to recover objects submerged at depths as great as 1,654 feet.

White whales in Project Deephear dive to depths of approximately 1,000 feet and are trained to whistle when they hear specific sounds.

Will project Hormuz be next?

Ballet dancer turned defense specialist Allison Barrie has traveled around the world covering the military, terrorism, weapons advancements and life on the front line. You can reach her at wargames@foxnews.com or follow her on Twitter @Allison_Barrie.