Humpback whales have a trick or two, when it comes to finding a quick snack at the bottom of the ocean. But how they pinpoint that meal at night, with little or no available light, remains a mystery.
Susan Parks, assistant professor of Biology in Syracuse University's College of Arts and Sciences, in collaboration with a consortium of other researchers, has been studying these unique feeding behaviors. Her research emphasizes the importance of specific auditory cues that these mammoth creatures emit, as they search the deep ocean for their prey.
Her findings are the subject of an article in the December issue of Scientific Reports (Evidence for acoustic communication among bottom foraging humpback whales, 2014), co-authored by researchers at Moss Landing Marine Laboratories, Oregon State University, Gerry E. Studds Stellwagen Bank National Marine Sanctuary, and the Whale Center of New England.
"Humpback whales are known to cooperate with others to corral prey near the surface," says Parks, who studies marine science and acoustic communication. "Recent studies suggest they may cooperate [with each other], when feeding on bottom prey, as well."
Parks was part of a collaborative multi-institutional consortium that has spent a decade monitoring Humpback feeding behaviors in the Gerry E. Studds Stellwagen Bank National Marine Sanctuary, off the coast of Massachusetts. Whales were tagged with special underwater recording devices so Parks could determine how specific acoustic sounds correlated with successful seafloor feeding.
The investigation revealed that whales make "tick-tock" noises while hunting together at night in deep, pitch-black water, but are silent when hunting alone.
On the menu? Mostly sand lance—eel-like fish known to bury themselves in the sand of the ocean floor. Parks suggests that whales' vocal sounds may help flush the sand lance out of hiding to where they're scooped up and eaten.
The clock-like sounds created by whales may also serve as a dinner bell of sorts for other nearby whales during late-night feedings.
"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 adds.
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