Tag Archives: toothed whales

Seeing in the Dark

New research sheds light on how porpoises hear in one of the world’s busiest rivers

The Yangtze finless porpoise, which inhabits the high-traffic waters near the Three Gorges Dam in China, is highly endangered, with only about 1,000 animals alive today. Scientists from Woods Hole Oceanographic Institution (WHOI) and their Chinese colleagues are using medical technology to shed new light on this species’ critical sense of hearing in a waterway punctuated by constant shipping, dredging, and underwater construction.

“We want to understand how they may be impacted by noise,” said Aran Mooney, a biologist at the Woods Hole Oceanographic Institution (WHOI) and a lead author on the study published online this week in the Journal of Experimental Biology. (more…)

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An Ancient Biosonar Sheds New Light on the Evolution of Echolocation in Toothed Whales

Some thirty million years ago, Ganges river dolphins diverged from other toothed whales, making them one of the oldest species of aquatic mammals that use echolocation, or biosonar, to navigate and find food. This also makes them ideal subjects for scientists working to understand the evolution of echolocation among toothed whales.

New research, led by Frants Havmand Jensen, a Danish Council for Independent Research | Natural Sciences postdoctoral fellow at Woods Hole Oceanographic Institution, shows that freshwater dolphins produce echolocation signals at very low sound intensities compared to marine dolphins, and that Ganges river dolphins echolocate at surprisingly low sound frequencies. The study, “Clicking in shallow rivers,” was published in the journal PLOS ONE. (more…)

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Ancient Whale Skulls and Directional Hearing: A Twisted Tale

*Skewed skulls may have helped early whales find direction of sounds in water*

Skewed skulls may have helped early whales find the direction of sounds in water and are not solely, as previously thought, a later adaptation related to echolocation.

Scientists affiliated with the University of Michigan and funded by the National Science Foundation (NSF) report the finding in a paper published online this week in the journal Proceedings of the National Academy of Sciences. (more…)

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