A stripped-down action camera held to the back of a sperm whale by suction cups returned footage that neither engineer Eric Stackpole nor whale biologist Rui Birado had ever seen before: two sperm whales speaking to each other, face to face, in the open ocean.
A DIY Tag Built in the Middle of the Night
The device at the center of the discovery was not a product of a well-funded laboratory. Rui Birado, a whale biologist who has spent decades studying sperm whales in the Azores, assembled the tag himself using a disassembled action camera, a light, a radio beacon, and suction cups engineered to grip a whale’s skin for several hours before releasing and floating to the surface. The entire rig was, by design, inexpensive and improvised.
Aboard the research vessel Ocean Explorer, the tag barely made it to deployment. Eric Stackpole and the team spent nights soldering and improvising repairs. At approximately 2:00 in the morning, the tag finally functioned. Birado was already on the small boat at dawn and placed the tag on the whale before Stackpole had even fully woken up.
The tension that followed was real: Would the tag flood? Would the battery die before the camera recorded anything meaningful? Would it ever surface? The answer to all three came when the team located the floating beacon, retrieved the tag, cracked it open aboard Ocean Explorer, and found the interior completely dry.
A Whale’s Descent and an Unexpected Second Voice
The SD card footage began at the whale’s back and head as it tilted downward and accelerated into the deep. Water particles rushed past the camera as the whale pushed deeper. The suction cups began to slip under the enormous water pressure, and one cup nearly lost its grip entirely — but one cup held, spinning the tag backward and revealing the whale’s tail, which Stackpole noted can reach 16 feet in width on some sperm whales.
As the whale descended, the camera’s microphone picked up rapid clicking: echolocation, the biological sonar sperm whales use to detect prey by listening for echoes reflected off their targets. The whale did not appear to catch anything on that particular dive.
As the whale ascended and light levels increased, a different sound emerged — a fast, patterned sequence of clicks. Birado identified these immediately as codas, the structured click sequences sperm whales use specifically to communicate with one another. Seconds later, a second sperm whale entered the camera’s frame. The two animals swam alongside each other, made physical contact, and exchanged codas back and forth for several minutes — an interaction Stackpole and Birado watched in stunned silence.
Sperm whales are the largest toothed predators on Earth and are known to dive beyond one mile in depth to hunt giant squid. Despite decades of research, direct observation of their social communication at depth has remained essentially impossible. The coda system has been studied acoustically from research vessels, but footage of two whales actively exchanging codas in close physical proximity — from the perspective of one of the whales — had never been recorded before this deployment in the Azores.
TED documented Stackpole’s account of the discovery as part of his broader work building low-cost underwater robotics designed to open ocean exploration beyond the limits of expensive institutional equipment. The Azores footage now stands as a landmark data point in cetacean communication research — proof that the most consequential discoveries are still accessible to anyone willing to spend the night soldering.