To mangle an F. Scott Fitzgerald quotation, the very big hear differently from you and me.

In this case, the very big were dinosaurs weighing up to 75 tons. According to a talk by Robert J. Dooling, given Tuesday at the meeting of the Acoustical Society of America, the beasts could not hear sounds as high as humans hear.

The meeting started Monday in Salt Lake City's downtown Hilton Hotel and concludes Friday. It has drawn hundreds of scientists, with 700 scientific papers to be presented during the week.

Dooling, professor in the department of psychology, University of Maryland, College Park, has reconstructed the hearing ability of dinosaurs.

A great extinction wiped out many animals at the end of the Permian era (about 230 million years ago), he said. But the archosaurs remained; these are the birds, crocodilians and dinosaurs. About 65 million years ago, another extinction killed off the dinosaurs, but other archosaurs — birds and crocodile-types — remain.

A study of the hearing apparatus shown in fossils and modern animals shows that the inner ears of archosaurs are much alike, Dooling explained during his lecture Tuesday morning. A brachiosaurus dinosaur and a canary have a similar bony ear structure, he said.

A small strip of tissue in the ear carries sensory cells. The structure to which this strip is attached remains in fossils and is seen in modern birds.

The range of hearing that birds have can be determined. "I have measured hearing in a lot of birds behaviorally," he said after the talk. "We've trained birds to peck keys" or do other things in response to sounds.

When they are trained, "we can do an auditory test on them," Dooling said. Birds may peck at a key when they hear a sound at a certain pitch but not when the sound is too high or too low for them to hear.

"Big birds hear better at low frequencies, small birds hear better at high frequency," he said. Their sensitivity can be correlated with the size of a small piece of bone that the sound-sensitive tissue is attached to.

Because dinosaur fossils sometimes preserve the same bone structure, Dooling has been able to calculate the dinosaurs' hearing range.

Fossils show that an ancient bird called Archaeopteryx, which was about the size of a chicken, could hear about the same range as birds of a comparable size today.

"Humans hear pretty well at low frequencies," he said. Humans and other mammals also hear a wide range of frequencies. But large dinosaurs would have had their best hearing at low levels and would not have heard high-pitched tones.

Why is that? Nobody knows for certain.

Asked to speculate, Dooling said a possibility is that dinosaurs were listening to low-frequency sounds that travel through the ground for miles.

"Just be walking, if you weigh a ton and a half or you weight 75 tons ... you're going to make a lot of low-frequency noise."

Elephants are thought to use their low-frequency hearing to locate herds of other elephants. Maybe something similar was going on with big dinosaurs.

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E-mail: bau@desnews.com