Deep beneath the Pacific Ocean, an unexpected discovery has shed light on one of the most elusive giants of the sea: the sperm whale. Known as the loudest animal on the planet, these massive creatures are rarely spotted in Monterey Bay, California, but a mysterious series of clicks recorded on an underwater hydrophone is rewriting what we know about their behavior and migration patterns.
For seven years, the Monterey Bay Aquarium Research Institute (MBARI) has been gathering audio from a hydrophone anchored to the seafloor, capable of recording sounds from as far as 100 miles away. During this time, researchers noticed an eerie, machine-like clicking that would build into a steady hum.
At first, it was anyone’s guess what creature or phenomenon was producing these sounds. But as they combed through mountains of data, U.S. National Science Foundation postdoctoral fellow Will Oestreich finally cracked the code: these clicks were the echolocation sounds of multiple sperm whales hunting in the pitch-black depths together.
For scientists, these clicks are a goldmine of information. Sperm whales produce what is considered the loudest biological sound on Earth, reaching up to a staggering 200 decibels. Each click, a fraction of a second long, is used for echolocation, allowing them to navigate and hunt in deep waters. But each click is more than just a loud noise; by analyzing their timing and patterns, researchers can infer body size, gender, and even social structures of the whales producing them.
This discovery showed that Monterey Bay is more than just a passing point—it’s a regular gathering spot, particularly during the late fall and winter, indicating a potential seasonal migration route through this nutrient-rich area.
The study, published in Movement Ecology, even detected “codas,” or unique sound patterns that appear to serve as cultural markers within different whale social groups. This hints at a fascinating complexity within sperm whale society, as these animals seem to use their clicks not only for hunting but also for communication, possibly even sharing information or identifying each other across vast distances.
These findings are more than just an academic breakthrough. With sperm whale populations still recovering from nearly two centuries of commercial whaling, every bit of knowledge helps build a case for more comprehensive protections. Noise pollution from ships, for example, could interfere with their clicking communication, posing significant risks for a species already under pressure. The Monterey Bay National Marine Sanctuary could be key to their conservation, especially as researchers learn more about this “whale highway” that may run through California’s coast.
And while sightings remain rare, Monterey Bay Whale Watch recently hit the jackpot, spotting a sperm whale for the first time in nearly eight years. The massive whale, with its characteristic small dorsal fin and distinctive curved head, surfaced just long enough for a spectacular show, leaving lucky onlookers in awe as it finally disappeared back into the depths.
Often spotted traveling in groups called pods, sperm whales are active deep sea hunters and can grow to be up to 59 feet long. Stream #SecretsOfTheWhales starting April 22 on Disney+ pic.twitter.com/nvfCRSRcF6
— National Geographic (@NatGeo) April 20, 2021
Sperm whales remain some of the ocean’s most formidable predators, diving to depths of up to 10,000 feet and holding their breath for over an hour while hunting squid, fish, and even sharks. Yet these “tigers of the deep sea” still have secrets left to reveal, and thanks to groundbreaking research and acoustic technology, we’re one step closer to understanding the lives of these ocean giants.
