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Beaked whale dives nearly 2 miles beneath the ocean - a record

Scientists have found a 20-foot whale that can dive an astonishing 1.8 miles beneath the ocean - a record for a mammal.

The record was reported this week in the journal Plos One.

The miraculous, extreme-diving whale is known as Cuvier's beaked whale (Ziphius cavirostris). Members of this species can be found in most oceans throughout the world, except for in the coldest arctic regions.

To survive the immense pressure changes it faces as it moves down the water column, Cuvier's beaked whales have evolved lungs and a trachea that collapse completely in the depths of the ocean and then pop back open as the whale moves to the surface to breathe.

To help the whale go for as much as two hours without breathing, it has so much of the oxygen-binding protein myoglobin in its muscle tissue that its muscles look dark purple, almost black.

"It is a really exciting species," said Erin Falcone, a biologist at Cascadia Research Collective in Olympia, Wash., and an author of the study. "They have the same basic needs that we do, but they function in this totally alien environment."

Although Cuvier's beaked whales have a wide distribution, they are still a bit of a mystery to scientists. They live far from shore, and spend most of their time deep beneath the ocean, making them difficult to observe. 

For this study, Falcone and her coauthors tracked eight whales over the course of three months off the coast of Southern California, not far from San Clemente Island. Using modified tranquilizer guns, the researchers shot satellite-linked tags on the dorsal fin of the whales. The tags transmitted information about where the whales went, as well as how far beneath the ocean they swam.

The deepest dive recorded was to a depth of 1.8 miles. The longest dive (made by a different whale) was two hours and 17 minutes. The average depth of all the dives recorded was .87 miles. The average length of all the dives was 67.4 minutes.

"We were pretty surprised when we saw the data," Falcone said. "The previous dive record of these whales was 1,188 meters (.7 miles), which was plenty deep. We spent a little time making sure the tag was functioning properly just to be sure the data was right."

She added that its possible that the whales may be able to go even deeper than what her team observed. 

"In the area where our animals are, the bottom depth isn't much deeper than 1.8 miles," she said. "In deeper water, they may go well beyond that."

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