An elephant called Chishuru is rewarded on the target mat for having completely a successful scent trial in Bela-Bela, north of Pretoria, South Africa. (AP Photo/Graham Alexander, Adventures With Elephants)

A recent Associated Press story is getting widespread attention: The U.S. Army Research Office is researching how elephants can sniff out explosives. The pachyderms wouldn’t be used in combat, but researchers hope to take what they learn and incorporate it into electronic sensors used by U.S. troops in the future.

It’s one of many times the U.S. military has used animals to assist in operations. Some of the examples are relatively novel, while others are controversial. Some examples:

Dolphins


A female bottlenose dolphin performs her daily exercises while her trainer, Dera Look, supervises at the joint Marine Mammal Research Program at Marine Corps Base Kaneohe Bay, Hawaii, in 2005. Photo by Journalist 2nd Class Jessica B. Davis/ U.S. Navy)

The U.S. Navy has used dolphins in a variety of ways, including to detect underwater mines. The work is expected to be phased out eventually, with underwater drones eventually replacing them, Navy officials have said. The U.S. Navy Marine Mammal Program oversees their use, and says that a dolphins’ ability to use sonar makes them well-suited for the job.

The dolphins are not trained to attack other ships, in part because they cannot tell the difference between U.S. and enemy vessels. The porpoises can be trained to swim alongside boats, ride inside them or transported by plane and helicopter, Navy officials said.

Sea lions


A California sea lion with the Navy Marine Mammal Program retrieves an object for his handler during the International Mine Countermeasures Exercise (IMCMEX) in Bahrain in October 2014. (Photo by Mass Communication Specialist 1st Class Kathleen Gorby/U.S. Navy)

The marine mammal program also has used sea lions because of their ability to find potential enemy swimmers near piers and ships and draw attention to them. In one case, the Navy developed the Shallow Water Intruder Detection System (SWIDS) program, using it overseas.

Rats

The U.S. Army has researched whether rats, with their keen sense of smell, could be used to find bombs. (U.S. Army photo)
The U.S. Army has researched whether rats, with their keen sense of smell, could be used to find bombs. (U.S. Army photo)

U.S. Army officials highlighted in 2012 their use of rats in the Rugged Automated Training System (RATS), which was developed to see how well the rodents could find bombs.

The use of rats could have several advantages, including that their small size would allow them to sneak into tiny spaces where larger animals and people cannot.

Mules


A U.S. Marine pets a pack mule at the Mountain Warfare Training Center in Bridgeport, Calif., in September 2014. (Photo by Cpl. Desire M. Mora/ Marine Corps)

U.S. service members have used a variety of pack animals in remote areas, including mules and donkeys. The practice is especially common with elite Special Operations troops, who frequently operate in small groups away from support from larger units that would provide logistical support.

A Special Forces document published in 2007 and posted online by the Federation of American Scientists detailed how the animals should receive care.

“Mules are intelligent and possess a strong sense of self-preservation,” it said. “A packer cannot make a mule do something if the mule thinks it will get hurt, no matter how much persuasion is used… many people confuse this trait with stubbornness.”

Pigs


The military still uses pigs in some medical training. This animal wasn’t one of them, and was photographed while U.S. doctors vaccinated livestock in Belize. (Photo by Tech. Sgt. Kali L. Gradishar/ Air Force)

The military has used pigs and goats in medical training for years, shooting them and then rushing to administer them medical aid so that troops are familiar with the unpredictability of providing combat care. The practice has been panned by People for the Ethical Treatment of Animals (PETA) and other organizations as inhumane, but the military has said it is vital to training.

The Pentagon acknowledged plans late last year to reduce how frequently it uses live animals, but will continue with combat trauma training.

Pigeons


Carrier pigeons used by the United States are shown here. (Photo released by the U.S. Coast Guard)

Long before the use of drones, the military used pigeons to deliver messages and conduct overhead reconnaissance of battlefields. The practice was especially common during World War I and World War II, when the Army oversaw tens of thousands of birds taught at the Pigeon Breeding and Training Center at Fort Monmouth, N.J.

The Smithsonian maintains a Web page dedicated to Cher Ami, a World War I pigeon that flew messages over France.

Dogs


U.S. Marine Lance Cpl. Nick Lacarra, a dog handler with Combined Anti-Armor Team 2, Weapons Company, 3rd Battalion, 3rd Marines, and Coot, an improvised explosive device detection dog, hold security in a field during a patrol with Afghan Border Police in Garmsir, Afghanistan, in January 2012. (Photo by Reece Lodder/ Marine Corps)

This is probably the most obvious way, given the widespread use of canines during the wars in Iraq and Afghanistan. A recent book, “War Dogs: Tales of Canine Heroism, History and Love,” captures much of the practice, outlining how the use of dogs in the military has evolved over the years.

Gizmodo put together a striking collection of photographs of military dogs in action a couple of years ago. And yes, some of the highly trained pooches wear “doggles” in combat.