Kamikaze dolphins in Iran? A brief history of dolphins in the military

Defense Secretary Pete Hegseth on Tuesday shut down the idea that Iran could weaponize marine mammals in the Strait of Hormuz as the war with Iran continues as he fielded a question about the potential use of “kamikaze dolphins.”

Experts say the idea isn’t as far-fetched as it may seem. Several countries, including the U.S., have a history of using dolphins in conflict areas, though not as weapons.

“I cannot confirm or deny whether we have kamikaze dolphins, but I can confirm they don’t,” Hegseth said at the briefing.

Hegseth’s comments came in response to news reports about the possibility. The Wall Street Journal reported April 30 that Iranian officials had said Iran could use “mine-carrying dolphins” to attack U.S. warships. It is not clear whether Iran has that capability.

The term “kamikaze” was popularized during World War II for pilots flying suicide missions into their targets.

The U.S. Navy Office of Information declined to comment further, referring CNBC to Hegseth’s Tuesday briefing.

The Strait of Hormuz has been largely blocked during the war, and on Sunday, President Donald Trump announced “Project Freedom,” an operation to free ships stranded in the strait since the onset of the conflict. Hegseth characterized the new mission as “separate and distinct from Operation Epic Fury,” the war the U.S. and Israel began waging Feb. 28. He said U.S. forces would not need to enter Iranian waters or airspace to carry out the operation.

Fresh attacks this week in the key waterway reignited fears that the impact on the global economy would worsen. Though a ceasefire between the U.S. and Iran officially remains in place, Iran attacked the United Arab Emirates, and the U.S. said it sank Iranian boats in the strait on Monday.

“Right now, the ceasefire certainly holds, but we’re going to be watching very, very closely,” Hegseth said.

Since 1959, the U.S. Navy’s Marine Mammal Program has trained bottlenose dolphins and California sea lions to detect mines and other underwater threats, conduct surveillance and locate and recover objects at sea, according to the Naval Information Warfare Center Pacific, a research and engineering laboratory for the U.S. Navy.

“Dolphins have been used in [military] exercises all over the globe,” said Scott Savitz, a senior engineer at global policy think tank Rand Corporation, and an expert on mine countermeasures.

During the Vietnam War, the Navy trained dolphins to detect swimmers and divers who were trying to access military facilities, Savitz said. The mammals also played a “key role” in detecting and clearing naval mines from the port of Umm Qasr during the Iraq War in 2003, he said.

According to Savitz, both dolphins and sea lions are “exceptional” at detecting underwater objects. Sea lions are commonly used to locate and recover objects in “cluttered” waters due to their excellent underwater eyesight, he said, while dolphins use echolocation, or biosonar, to search for naval mines in open water.

Dolphins’ biosonar is often more accurate than electronic sonar, according to the Naval Information Warfare Center Pacific. They “can not only locate objects, but differentiate them with a greater degree of facility than the machines that we’ve been able to develop for this purpose,” Savitz said.

The Soviet Navy also trained dolphins for defense during the Cold War, though the unit was transferred to Ukraine after the fall of the Soviet Union, according to an NPR report from 2022, citing an analysis from U.S. Naval Institute News. The Russian military reportedly revived its dolphin program after seizing Ukraine’s defense dolphins in 2014 during the annexation of Crimea. In 2022, satellite imagery identified two dolphin pens in the Sevastopol harbor, the analysis found.

The use of dolphins in military operations raises complex questions, experts say — not just about whether countries like Iran possess trained marine animals, but whether they have developed the expertise to work effectively with them. 

“It’s a challenge for humans to learn how to work best with dolphin capabilities,” Savitz said. 

The question isn’t “whether or not the Iranians may have physical animals with some training, but whether the Iranians have trained themselves” to work with the dolphins, he said.

Few protections exist for animals in armed conflict although there are some legal strategies based on international humanitarian law that could be used, according to Chris Jenks, a research professor of law at Southern Methodist University.

A representative for the American Society for the Prevention of Cruelty to Animals referred CNBC to the organization’s general position on military animals. The nonprofit “recognizes the value” of animals for military functions, but said that “animals should not be unnecessarily put at risk or sacrificed in the service of our country.”

“Military animals should be humanely trained and responsibly maintained, and commitment to the animals’ well-being must extend beyond the period of military service,” according to the ASPCA’s site.

Savitz said he has worked with the Marine Mammal Program “intermittently” for 25 years. He said that “dolphins and sea lions love the program.”

“They get exercised every day in open waters,” he said. “They like the free fish. They like playing with humans. For them, it’s a game, just as with drug sniffing dogs or explosive sniffing dogs.”

No marine mammal has been harmed during a military operation, Savitz said: “They are living out healthy lives.”