Sperm whales are the noisiest animals on earth. This may come as a bit of a surprise if you’re just listening to a recording of a clicking sound that sounds like a combination of Morse code and popping popcorn.
What do those sounds tell us about their behavior and ecosystems?
Ryan’s group worked with collaborators at the Naval Postgraduate School and the University of Washington’s Ecosystem Sentinel Center to analyze millions of whale calls recorded over seven years in the Monterey Bay National Marine Sanctuary.
The spacing between echolocation clicks emitted by sperm whales can indicate the age and sex of individual whales. These sounds can also reveal whether the whale is actively hunting or has successfully captured prey.
The researchers also learned that these animals are abundant in Monterey Bay during the winter, providing strong evidence that sperm whales migrate seasonally through the Northeast Pacific Ocean.
Scientists once thought the opposite, based on research further north in the Gulf of Alaska, where whale calls were found to peak in the summer.
These patterns suggest that seasonal migration, previously unrecognized in sperm whales, is likely consistent with changes in the North Pacific transition zone, a biologically rich region where cold and warm ocean waters meet. It suggests that.
“What we’re actually hearing is a very unique seasonal migration in this deep-sea top predator,” said MBARI postdoctoral fellow William Oestreich, who led the study.
These findings support the idea that there are seasonal changes in the deep sea environment and that top predators like sperm whales play an important role in maintaining the health of marine ecosystems. .
An underwater microphone, or hydrophone, installed at MBARI’s wired deep-sea observatory, the Monterey Acceleration Research System (MARS), in the heart of the Monterey Bay National Marine Sanctuary. The treasure trove of acoustic data recorded by this hydrophone provides researchers with an important lens into marine life and ecosystems. (Monterey Bay Aquarium Research Institute)
Sperm whales are the largest toothed predators with the largest brains in the animal kingdom. They can grow up to 52 feet long and weigh up to 45 tons. Despite their size, they are still full of mystery. “These animals are very cryptic. They are very deep divers,” Oestreich said.
They hunt squid and fish by diving hundreds or even thousands of meters below the ocean’s surface, using echolocation to locate prey in the darkness of the deep ocean. Their distinctive clicking sounds provide scientists with valuable information about their behavior.
“Animal sounds contain a wealth of information about who they are and what they’re doing, and it’s up to us as researchers to decipher their meaning,” Oestreich said. said.
Map showing the detection range of echolocation clicks of sperm whales (Physeter Macrocepalus) by submersible or underwater microphones at MBARI’s wired deep-sea observatory in the heart of the Monterey Bay National Marine Sanctuary. Hydrophones can detect sperm whale clicks from up to 100 miles away. (William Oestreich © 2024 MBARI, bathymetry provided by NOAA National Centers for Environmental Information)
MBARI researchers aim to support conservation efforts for sperm whales and other endangered species through acoustic data analysis. This research provides important insights for decision makers working to protect these important marine environments and their inhabitants.
“There’s a lot of value in understanding the lives of these animals a little deeper, just for pure fascination and appreciation, but also, hopefully, to better protect the ecosystems they depend on. ”Ostreich said.
