Rare video captures orca pod hunting a pygmy sperm whale

As the whale watching boat slowly approached, the passengers saw something strange in the water—an 80-foot cloud of red-brown liquid. Just minutes later, an orca hurled a small whale into the air. Dark red fluid gushed from its body. A member of the three-orca pod forced the whale under the water, holding the thrashing animal below the surface.

One of the orcas then approached the boat with its prey in its mouth, “and then I see her looking at us like, hey, look what I got?” says Camila Alejandra Dávila Pardo, a marine biologist at Blue Safari Madeira, a whale and dolphin watching tour group. “I never thought for a second it was going to be a mammal.” 

What Dávila Pardo didn’t know at the time was that she may have documented the first known instance of orcas hunting a marine mammal in Madeira, a Portuguese island territory in the northeast Atlantic Ocean. Dávila Pardo recently published her account of the whale attack in the journal Marine Mammal Science where she and her coauthors noted finding no other examples of such behavior in the region. However, it’s the fourth global record of orcas hunting pygmy sperm whales, Dávila Pardo says.

The remarkable sighting is more than a spectacle. It gives scientists a new example of orcas’ complex predator behavior and raises concerns that they might prey on some of the region’s endangered marine mammals.

A unique self-defense strategy

“When I saw the picture for the first time, I thought “oh my God, that’s blood. It was very dark,” says Renaud de Stephanis, a marine biologist at cetacean conservation organization CIRCE who was not involved in the study.

But it wasn’t blood. When pygmy sperm whales feel threatened, they release a reddish intestinal fluid as a form of self-defense. Like a squid’s ink, this substance obscures the whale, giving it a chance to get away.

“But it didn't work on the orcas, clearly,” says Dávila Pardo. With the killer whale’s sophisticated echolocation, “it's like having a military submarine tracking you.”

Pygmy sperm whales are deep diving animals that live far from shore so are rarely seen by humans. 

They “prefer offshore habitats usually in waters of 400 meters (1,300 feet) or more,” Rob Lott, campaign coordinator at Whale and Dolphin Conservation, wrote in an email. “These orcas, as apex predators, have developed a coordinated foraging strategy that can efficiently target this deep-water species.”

Killer whales are only seen around Madeira a handful of times each year, and not much is known about the local population. Although orcas had been recorded hunting whales and dolphins in the nearby Azores and the Canary Islands, the video of such a rare event in Madeira still surprised scientists. 

Neither Lott nor de Stephanis are aware of previous records of killer whales hunting pygmy sperm whales in Madeira.

Understanding a mysterious predator

When Dávila Pardo had spotted the three individuals earlier that day, she thought they might start hunting. “There's no reason for these animals to stay this long,” she told her guests aboard the ship.

More clues soon started to emerge.

Dávila Pardo had never heard of pilot whales and beaked whales interacting, but she’d also seen the two species together earlier that same day.

“I said, ‘maybe there's something bigger in the area, and that's why the beaked whales are trying to defend themselves by finding shelter with the pilots’,” she says. Pilot whales have previously been seen swimming after orcas, perhaps to scare them off. The gruesome hunting scene followed shortly after.

Around the world, there are several distinct types of orcas—known as ecotypes—that have different appearances, behaviors, and prey. Many eat fish, offshore killer whales have been recorded hunting sharks, and orcas in the Pacific Northwest are best known for hunting and eating mammals like seals.

Evidence that the Madeira population also eats mammals is “just a fascinating discovery,” says de Stephanis. He had heard theories that orcas in the area might feed on marine mammals, but this confirmation, and that they attack deep diving species, was particularly surprising. 

Lott was surprised that the three individual orcas weren’t found in photo identification databases from the Madeira Whale Museum and the citizen science program Happywhale, which might suggest they are a transient pod. “Adding these ‘mystery orcas’ to the literature will contribute to a larger scale understanding of orca movement,” he says.

If killer whales in Madeira are hunting mammals, it might also spell trouble for the island’s critically endangered monk seals of which there are fewer than 30 adults. “Are we looking into something that could possibly be a problem for this population?” wonders Dávila Pardo.

To answer this and additional remaining questions, she says she and other local experts need more observations of their behavior. By sharing her paper, she wants to get out the message: “these are our orcas. Have you guys seen them around? We need help.”