Sound the dinner bell!
Biologists studying the feeding behaviors of humpback whales have shed light on a long-standing mystery: How do whales find food at the bottom of the ocean in pitch-black darkness? The answer, it turns out, may lie in a newly observed sound which certain humpbacks use during nighttime hunts on the seafloor.
Susan Parks, the lead author of a study published recently in the journal Scientific Reports, told The Huffington Post that researchers listened in on the noises made by a group of humpbacks hunting at night off the Massachusetts coast. The whales, which had been outfitted with acoustic recording tags, sometimes made a "weird sound that sounded like a ticking of a clock," Parks said.
Researchers think the whales might make this squishy tick-tock sound -- sort of a mix between a frog’s croak and a plunger -- to force burrowed prey to emerge from their sandy hiding places.
The sound also might act as a dinner bell for nearby whales who may be listening for signs of a successful hunt. Hearing the ticking noises might prompt these whales to move in and feast alongside the hunters.
“Hints of behavior suggest that other whales who overhear the sounds are attracted to them and may eavesdrop on other whales hunting for food,” Parks said in a statement.
The researchers noticed that the whales used this sound when hunting together and were silent when they hunted alone. Humpbacks have been known to “cooperate with others to corral prey near the [ocean] surface,” Parks said in a statement, but this new research suggests that they also communicate and work together when scouring for prey on the dark ocean floor.
"The part I’m really excited about," Parks told HuffPost, "is that we think they’re using it to communicate to other whales to time behavior with other whales in the dark, because we only detect the sound at the bottom and also hear other whales around."
According to Parks, this study is a continuation of humpback whale research that began in the 1970s. "It’s 2014," she told HuffPost, "and we’re still discovering new sounds that they make. No one has ever recorded this sound before. It’s cool that just five miles offshore of Boston is something that we’re still discovering today.”
Parks, an assistant professor of biology at Syracuse University, co-authored the study with researchers from Moss Landing Marine Laboratories, Oregon State University, Gerry E. Studds Stellwagen Bank National Marine Sanctuary and the Whale Center of New England.