Scientists Detect Silent Whales Using Internet Cables

Nearly 1,000 feet below the Norwegian coast, scientists just spotted something remarkable: a blue whale swimming silently through the deep ocean, detected not by sound, but by the water it displaced as it moved.

The discovery happened on a fiber-optic cable no wider than a human hair buried beneath the seabed. When the massive whale dove and swam overhead, the pressure waves from its body stretched the tiny glass cable in microscopic ways that researchers could measure from shore.

Marine geophysicist Martin Landrø and his team at the Norwegian University of Science and Technology were already using these telecommunication cables to detect submarines and ships. They fire laser pulses down the cables, and when something large passes overhead, the pressure disturbances show up in the data.

But whales presented a puzzle. Scientists typically find whales using hydrophones that pick up their calls, like underwater microphones. In 2022, Landrø's team proved they could hear whale vocalizations through the cables too.

The breakthrough came when they detected a blue whale calling at the surface, then watched it dive into complete silence. The same disturbance pattern they'd seen from submarines appeared in their data. The whale was moving near the cable, displacing enough water to create detectable pressure waves, even though it made no sound at all.

Blue whales are Earth's largest animals, sometimes reaching 100 feet long. When something that massive moves through water, it creates ripples that spread outward like dropping a rock in a pond. These low-frequency waves travel down to the seafloor and stretch the buried cables in ways scientists can now measure and interpret.

The team used century-old physics equations originally designed to study collapsing bubbles. Despite the size difference, the same principles helped them distinguish a diving whale from passing ships or submarines.

The Bright Side

This technology opens an entirely new window into whale behavior at depths where they've been invisible to researchers. Scientists currently attach suction tags to whales at the surface to study their dives, but these tags fall off quickly and provide limited data.

Now researchers can potentially monitor whales year-round using the vast network of telecommunication cables already crisscrossing the ocean floor. They could track seasonal patterns, daily behaviors, and study species like gray whales that feed on the seafloor, all without disturbing the animals or deploying expensive equipment.

Marine engineer Shima Abadi from the University of Washington calls it "an important first step" in proving this approach works. The same cables connecting the world's internet could help us understand and protect the ocean's giants in ways never before possible.

The whales swimming beneath us just became a little less mysterious.