For decades, the US government has been training animals to keep us safe in times of both war and peace. It's amazing what these animals can do -- and how much science and technology are behind their missions.
Take, for example, the US Navy's Marine Mammal Program. The long-running program trains dolphins and other animals to perform aquatic tasks that human divers are unable to.
In this photo, a bottlenose dolphin wearing a locator beacon device leaps out of the water during a training exercise in the Persian Gulf. The animal is being trained to locate mines hiding in shipping lanes.
One of the Marine Mammal Program's dolphins is seen holding a bite plate in its mouth in this underwater training photograph.
In the field, these bite plates might contain surveillance equipment or a tethered line to be hooked onto an underwater object.
Sea lions are a big part of the US Navy's Marine Mammal Program.
In this photo, a California sea lion named Jack salutes his handler following a 2014 training exercise in Manama, Bahrain. Sea lions are used by the Navy to recover important equipment from the ocean floor faster than human divers can.
Though the US Navy Marine Mammal Program now focuses mainly on training sea lions and dolphins, sharks were once trained for naval use in swimmer protection missions.
They could be America's smallest living spies: The Defense Advanced Research Laboratory (DARPA) has been conducting research into creating insect cyborgs for some time.
Scientists implant electronics into the creatures when they're in their larval stage. As the insects mature, the electronics become fully embedded and hidden.
The resulting cyborg insects can be easily tracked, making them useful for surveillance missions.
Bees, as scientists have learned, have an incredibly sensitive sense of smell. This is why DARPA has singled out honeybees for use in bomb-detection missions since 1999.
Scientists train bomb-detecting bees by exposing the insects to the scent of explosives as they feed on sugar water. When a honeybee encounters the same smell in the wild, it will instinctively raise its proboscis to try to feed as a Pavlovian response.
Small radio transmitters are used to track the location of the bees in the field. Digital cameras and specialized software, meanwhile, are trained to detect the waving of the probosces at a distance.
The US Navy tested 19 different aquatic species as part of its Marine Mammal Program. Ultimately, it was decided that bottlenose dolphins and sea lions were best equipped for its underwater missions.
Dolphins are valuable to the Navy because of their highly evolved sonar. Sea lions, meanwhile, have tremendous underwater vision -- great for spotting enemy divers.
As far as we know, the Navy doesn't train marine animals for attack missions. Animals are, however, recruited for defensive purposes.
Sea lions in the Navy's MK 6 team, for example, are trained to carry specialized handcuffs in their mouths. The lions can attach these tracking-enabled cuffs to underwater intruders when detected.
In its first ever successful recovery mission, a sea lion from the Marine Mammal Program's MK 5 team recovered an antisubmarine rocket from a depth of 180 feet.
Naval sea lions have also been trained to recover crash-test dummies from the sites of plane crashes.
During the Vietnam War, rumors began circulating that the US Navy was training dolphins to kill enemy divers.
The Navy denies this, however, insisting its marine mammals have never been trained to attack humans.
Killer whales have been trained as part of the Navy's Marine Mammal Program as well.
The magnificent animals are prized for their ability to dive to extreme depths in colder waters.
Naval trainers have been able to harness the orcas' underwater auditory sensitivity for use in object-recovery missions.
The whales are also adept at spotting mines with their sonar.
The Navy has also experimented with using belugas, or white whales.
Here, a beluga marks an underwater training target during a Naval exercise.
A living, breathing cat seems like a highly unlikely (and perhaps highly unethical) place to embed a listening device. But that was exactly the goal of a 1960s experiment by the CIA called Operation Acoustic Kitty.
Now-declassified documents detail how, in an hour-long procedure, veterinarians implanted a microphone in a gray-and-white female cat's ear canal and a radio transmitter at the base of the cat's skull. A wire ran under the cat's fur, using its tail as an antenna.
CIA leaders planned to release the cat near the Soviet embassy in Washington, D.C., hoping it would pick up valuable data.
But things did not go as planned...
Shortly after the government built its bionic kitty, problems began to arise. Every time the cat got hungry, it would wander away from its surveillance targets to look for food.
Scientists "solved" this problem by putting the cat through more expensive surgery to eliminate its sense of hunger.
After $20 million worth of training and surgery, the feline secret agent was finally sent out on its first official mission: Eavesdrop on two Soviets having a conversation on a park bench.
Sadly, however, she was never able to complete her mission. Shortly after being released by a CIA reconnaissance van, the cat was hit and killed by a taxi cab.
Project Acoustic Kitty was abandoned as a total loss in 1967, with a final report stating that it was not practical for live cats to be used as listening devices.
The CIA spent an estimated $20 million on the failed program -- the equivalent of $142 million today when you adjust for inflation.