Right to Quiet Society Noiseletter
Spring 2014, page 2

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Ancient whale fossils reveal early origin of echolocation

By Tia Ghose, Staff Writer

An ancient whale used sound beams to navigate and stalk prey 28 million years ago, an analysis of a new fossil suggests. The new whale species, called Cotylocara macei, contains air pockets in the skull similar to those used by porpoises and dolphins to send out focussed sound beams. The discovery pushes back the origins of the ability, called echolocation, to at least 32 million years ago, said study co-author Jonathan Geisler, an anatomist at the New York Institute of Technology. "It suggests echo-location evolved very, very early in the history of the group that involved toothed whales," a group that includes sperm whales and killer whales, as well as dolphins and porpoises, Geisler said.

Fossil whale

About 10 years ago, scientists unearthed a complete toothed whale skull, along with a few neck vertebrae and some ribs in a fossil-rich region near Charleston, South Carolina, an international collector named Mace Brown acquired the find, and then invited Geisler to take a look at it. The new species is named after the collector.

The ancient whale, which was about 28 million years old, grew to about 10 feet (3 metres) long and looked some-what similar to modern-day dolphins or small cetaceans, though they are not closely related. It likely lived in shallow marine environments, such as the mouth of an estuary or a little further offshore, Geisler said.

Early echolocation

C. macei also had several distinctive features, including bone density variations and several deep air cavities, including one on top of the skull and one on either side of the base of the snout, Geisler said. The skull of the ancient whale C. macei, reveals distinctive density variation and shapes suggestive of echolocation.

Those air sinuses looked similar in purpose to those found in toothed whales, or odontocetes. In odontocetes, the air sinuses help them form nearly continuous, focussed sound beams to investigate or search for prey in dark or muddy water. They then process the reflections of those sound beams through internal ears on the side of their heads, or through air spaces between their jaws, to create a sound-based map of the world around them.

"Odontocetes don't produce sound in their voice box, it's originated in the face," Geisler told Live Science. The ear bones and soft tissue from the whale weren't preserved, so they don't know for sure how the whale's echolocation would have sounded or how it processed the reflections from sound beams they sent out, Geisler said. The new discovery suggests that echolocation evolved very early in whale evolution, likely soon after odontocetes diverged from the ancestors of baleen whales. The findings were published Mar. 12, 2014 in the journal Nature.

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Owls’ silent flight may lead to quieter planes and subs

By Dene Moore

Inspired by a collection of Canadian owl feathers, an international team of engineers is studying the nocturnal birds of prey, hoping the mysteries of their stealthy flight might lead to improvements in the design of everything from air-craft to submarines. The team has studied the design of owl wings in microscopic detail to try to figure out how the majestic birds remain so silent in flight, swooping down on prey without warning.

“Owls are remarkable predators. They hunt in almost complete darkness, using only their ears to weave around and capture their prey,” said Justin Jaworski, an assistant professor in Lehigh University’s Department of Mechanical Engineering and Mechanics and one of the lead researchers on the project. A great grey owl can go through a couple of inches of ice, can hear through that, to get its prey. They are quite fantastic birds.”

It was during a visit to Cambridge University a few years ago that a retired colleague gave Jaworski and his cohorts several of his collection of owl feathers, picked up from the Owl

Foundation during a visit to Ontario. He piqued their interest in finding out how the owls are engineered for such stealth, and their interest piqued others. “Those have been our inspiration for a lot of our theoretical modelling,” he said in a recent interview. “We’re trying to figure out by looking at the physiology of the wings, comparing them to other birds and then try to model - both through theory and replicate experiments - trying to figure out what the physics are that are making them quieter than other birds.”

There are three wing features that are unique to owls. They have a comb of stiff feathers along the leading edge of the wing - a group of evenly spaced fibres - a flexible fringe on the trailing edge of the wing and a soft, downy material covering the top of the wing. Jarowski and the other four researchers from Atlantic University, Virginia Tech and Cambridge are trying to figure out how each of these features contributes to the owls’ acoustic abilities. In particular, they have looked at the serrated trailing edge of the wing - the area that creates the most noise in birds and airplanes.

- The Canadian Press

"When I come home late in the evening I absolutely cringe as I plug in my car because I know the horn will sound. It's so rude that sometimes I'll just drive on gasoline the next day to avoid disturbing my neighbors."

Wonderful quote from the Chevy Volt online forum

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