Hvaldimir, a white beluga whale thought to have been used as a Russian spy, was found dead last weekend under what animal rights organisations say were suspicious circumstances in Norway near Russian waters while wearing a harness.

The beluga – named after the Norwegian word for whale, “hval” and part of Russian President Vladimir Putin’s first name, “dimir” – was pulled out of the water using a crane and transported to a nearby harbour for examination by experts.

In 2019, the beluga gained worldwide attention when fishermen found him off the Norwegian coast. Hvaldimir was wearing a camera harness with the inscription “Equipment St. Petersburg”. That prompted suspicions in the West that the whale might have been a part of a Russian navy programme that trained aquatic animals as spies — though others argued that Hvaldimir might have been trained to help with therapy for children with disabilities.

Marine biologist Sebastian Strand, the founder of the Norwegian nonprofit Marine Mind, which advocates for the protection of oceans and marine life, has been tracking Hvaldimir for more than three years.

“Unfortunately, we found Hvaldimir floating in the sea. He has passed away but it’s not immediately clear what the cause of death is,” Strand told Norwegian public broadcaster NRK.

Yet, while the cause of the whale’s death is not clear, and — like the best secret agents — Hvaldimir never left any firm evidence to confirm whether he was a spy, his story is only the latest in a long history of nations using animals as spooks.

So who was Hvaldimir, which animals have been used for spying before — and who has been the most successful?

Who was Hvaldimir?

Hvaldimir, the 4.2-metre (14-foot) long and 1,225kg (2,700-pound) whale was first spotted in 2019 by fishermen near the northern Norwegian island of Ingoya. He is believed to have been 14 or 15 years old when he died, which is less than half the average lifespan of a beluga whale, roughly 30 years.

Before his death, the beluga would be seen in several Norwegian coastal towns and has even been recorded over the years interacting with fisherman and even retrieving a kayaker’s dropped GoPro.

Controversy over how Hvaldimir died

Marine Mind is not the only nonprofit marine organisation that has followed this famous beluga in recent years.

Since 2019, OneWhale, another nonprofit organisation, has had a team present in Norway, closely monitoring Hvaldimir’s activities, conduct, and engagements with the public.

Regina Haug, the founder of OneWhale, suspects Hvaldimir’s passing “was not a natural death”.

In a series of video messages on Instagram, Haug said: “The misinformation that is being spread, is that Hvaldimir did not have any damage to his body and no noticeable injuries at his time of death. It’s been hypothesised Hvaldimir died of natural causes such as heart failure.”

But, she said, there were “some very noticeable holes pouring with blood from his [Hvaldimir’s] body”.

Have other animals been used as spies?

Yes, plenty of them. Before the advent of sophisticated listening devices and miniature spy cameras, some the size of shirt-button, the need to move secretive information over long distances was a challenge.

Carrier pigeons have been used to send messages and notes for centuries, including during wars. During World War I, the German military used pigeons fitted with specially designed cameras for surveillance.

Pigeons were subsequently used for spying by the Allies during World War II. According to declassified documents, the CIA’s Operation Tacana in the 1970s flew pigeons fitted with miniature cameras into the Soviet Union to take photos of sensitive sites.

Not just pigeons, cats, whales, dolphins, birds of other kinds, and even dead animals have served as covert operatives. The CIA, for instance, once trained ravens to plant bugging devices on window sills.

Cloak-and-dagger dolphins

During the Cold War, the Soviet navy implemented various programmes involving marine mammals, one of which involved training dolphins in the vicinity of Sevastopol. The US Navy has also been known to use dolphins under the Marine Mammal Program (MMP), which has used the animals for underwater surveillance and intelligence gathering.

In the 1960s, the CIA launched Project OXYGAS under which dolphins were trained to attach explosive devices to enemy ships. Two captured wild bottlenose dolphins were used for the programme.

In 2019, a declassified agency report from the programme said OXYGAS was “considered more than justifiable providing feasibility could be demonstrated to deliver a simulated weapons package over an open sea distance to a propellor of a moored PT [patrol torpedo] boat”.

According to a British intelligence report last year, Russia created a mammal programme to train dolphins to detect and “counter” enemy divers at its Sevastopol Black Sea fleet naval base in Crimea.

At the time, satellite imagery from the British military showed a substantial increase in the number of floating mammal pens in the harbour of Sevastopol from April to June 2023.

Stealthy cats

Dolphins are known to be among the smartest animals in the world. But cats are thought to be clever too.

In the 1960s, the CIA developed another project called Operation Acoustic Kitty. The goal was to attach microphones in the acoustic ears of cats to secretly record conversations taking place around them — such as near Soviet diplomats and agents.

The thinking was clear: a cat, a common household pet, would be suspicious neither in public nor in closed spaces. Though the technology worked, cats are not easy to control. During field testing, they could not be controlled and instructed to go to exact locations, resulting in the “spy cats” going to any place they wanted to go.

The programme was eventually cancelled in 1967. It cost an estimated $20m.

Dead rats

The CIA’s experimentation was not limited to cats.

A common practice in spycraft is that of the dead drop — where an agent leaves a message or document at a predetermined spot for another person to pick up.

During the Cold War, the CIA’s Office of Technical Services suggested using dead rats to conceal secret messages for officers to pick up. The dead rat’s carcass would be treated with a preservation agent, with the insides hollowed out to hide notes, secret photos or film. The idea: most humans would find the body of a dead rat so repulsive they would not come anywhere close to it.

But field testing showed up a challenge the agency had not thought of – dead rats might make humans turn up their noses, but they make cats lick their lips. Cats would pick up the dead drops before the agent they were meant for could get to it.

So the CIA tried to soak the preserved rat carcasses in hot sauce and cayenne pepper, to make them less palatable to cats. The strategy had mixed results. They eventually settled on wormwood oil which served as an effective deterrent.

The best spies: The winner is …

But while cats and dead rats might have their advantages, spy agencies have over the years returned — time and again — to an age-old cadre of agents: pigeons.

One very successful spy programme run by British intelligence during World War II was a pigeon messenger scheme known as Operation Columba. Homing pigeons gathered intelligence on German military activities and sensitive military positions.

The tiny messages written on rice paper were tucked in canisters and tied to the bird’s leg. Many of these secretive messages would include Nazi troop movements, reports on new Nazi weapons, and planned rocket attacks.

According to Gordon Corera, author of Operation Columba: The Secret Pigeon Service, British intelligence dropped 16,000 homing pigeons over Nazi-occupied Europe, from Bordeaux, France to Copenhagen, Denmark, between 1941 and 1944.

They delivered about 1,000 messages back to London, using their superpower — an almost surreal ability to find their way home, no matter where they are left.

Birds, in general, have also inspired spy technology. In August, China unveiled a military spy drone disguised as a bird.

But pigeons are also victims of their own success as spies.

India’s pigeon spy obsession

In May 2020, villagers in Indian-administered Kashmir captured what they suspected was a spy pigeon from Pakistan. The bird that was captured was found with a ring carrying a set of numbers. The villagers handed the pigeon to local police, who started an investigation to decrypt the number — suspecting it was a code.

But eventually, they concluded that the pigeon was not a spy — and released it.

In October 2016, another pigeon was found with a note threatening the Indian prime minister. The pigeon was discovered in Pathankot in the northern Indian state of Punjab and taken into custody.

In May 2023, a pigeon found in Mumbai was detained for eight months on suspicion of being a Chinese spy. The alleged spy pigeon was found with rings tied to its leg and what appeared to be Chinese writing on the underside of its wings. Authorities eventually concluded that it was a Taiwanese racing bird, and released it in February.