<\/img> <\/p>\n
Blue whales have changed their songs.<\/p>\n
It’s the same old tune,
\nbut the pitch of the blues is mysteriously lower — especially off the
\ncoast of California where, local researchers say, the whales’ voices
\nhave dropped by more than half an octave since the 1960s.<\/p>\n
No one
\nknows why. But one conjecture is that more baritone whales indicate
\nhealthier populations: The whales may be less shrill because they’re
\nless scarce and don’t have to pipe up to be heard by neighbors.<\/p>\n
The
\ndiscovery was accidental. Whale acoustics researcher Mark McDonald was
\ntrying to track blue whales’ movements using data from Navy submarine
\ndetectors. He had created a program to filter out the blues’ songs from
\na din of ocean noise captured by these instruments.<\/p>\n
But he kept having to rewrite the code. Each year, it seemed, the whales sang at a lower pitch.\n<\/p>\n
At So the researchers scoured military data and seismograph readings for clues about what blue whales used to sound like.<\/p>\n A The tapes eliminated all doubt: In the Beach Boys’ era, With more work, the researchers were able show Blue whales are Their song is barely audible to the human ear — a deep bass growl with very long wavelengths befitting very long whales.<\/p>\n The The The rumble of It’s also So they put themselves in the whales’ shoes. McDonald Among whales, he said, depth of voice may After the whales were hunted Efforts "This If whale songs Oceanographer But He was on a boat, using headphones, and one passed. — Jill Leovy<\/p>\n Animal news on the go: Follow Unleashed on Facebook<\/a> and Twitter<\/a>.<\/strong><\/p>\n Photo: A blue whale surfaces near Dana Point, Calif. Credit: Marc Carpenter \/ Associated Press Blue whales have changed their songs. It’s the same old tune, but the pitch of the blues is mysteriously lower — especially off the coast of California where, local researchers say, the whales’ voices have dropped by more than half an octave since the 1960s. No one knows why. But one conjecture is that more […]<\/p>\n","protected":false},"author":4172,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[],"class_list":["post-262692","post","type-post","status-publish","format-standard","hentry","category-news"],"_links":{"self":[{"href":"https:\/\/mereja.media\/index\/wp-json\/wp\/v2\/posts\/262692","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mereja.media\/index\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mereja.media\/index\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mereja.media\/index\/wp-json\/wp\/v2\/users\/4172"}],"replies":[{"embeddable":true,"href":"https:\/\/mereja.media\/index\/wp-json\/wp\/v2\/comments?post=262692"}],"version-history":[{"count":0,"href":"https:\/\/mereja.media\/index\/wp-json\/wp\/v2\/posts\/262692\/revisions"}],"wp:attachment":[{"href":"https:\/\/mereja.media\/index\/wp-json\/wp\/v2\/media?parent=262692"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mereja.media\/index\/wp-json\/wp\/v2\/categories?post=262692"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mereja.media\/index\/wp-json\/wp\/v2\/tags?post=262692"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\nfirst, the researchers thought it was a quirk. But after a couple of
\nyears of adjusting for lower frequencies, "we knew there was something
\nstrange going on," said John Hildebrand, an oceanographer at Scripps
\nInstitution of Oceanography<\/a> in San Diego and co-author of the study published recently in Endangered Species Research<\/a>.\n<\/p>\n
\nretired Navy scientist directed Hildebrand to a trove of tapes stored
\nat Sea World. The delicate old reels were the size of dinner plates. It
\nturned out they contained snippets of blue whale songs from 40 years
\nago.<\/p>\n
\nblue whales’ voices, while nowhere near falsetto, had been distinctly
\nhigher pitched.<\/p>\n
\nthat blue whales worldwide are using deeper voices lately. Some have
\ndropped their calls by only a few tones, but all showed a steady
\ndecline. "It was baffling," Hildebrand said.<\/p>\n
\nshrouded in mystery as it is. Sleek, mottled and silvery, they are rare
\nand don’t reveal much. They don’t leap on the surface as much as
\nhumpback whales do. They might, if really flustered, slap their tails
\non the water. More often, they quietly sink, Hildebrand said.<\/p>\n
\ntone is so deep that if played in a small room, it’s hard to hear: The
\nlong-period sound waves extend beyond the walls. But play a recording
\nvery loudly, in a large auditorium, and "you feel it in your chest as
\nmuch as you hear it," McDonald said. "It’s awesome."<\/p>\n
\nresearchers pondered possible causes. Warmer temperatures? More acidic
\nseas? Such factors affect the way sound moves through water, but not
\nenough to explain the change, Hildebrand said.<\/p>\n
\nshipping traffic is thought to affect marine mammals. But the
\nresearchers argue that if whales were just trying to be heard above the
\nfray, they would adopt higher, not lower, voices.<\/p>\n
\npossible that the low voice is just a fad. Biologists talk about whale
\n"culture," and blue whales tend to be conformists. But researchers have
\nsaid they doubt that a random, learned behavior could spread all over
\nthe globe.<\/p>\n
\nsurmised that whales would rather not sing in higher voices if they
\ndidn’t have to. They prefer deep and manly — "a lower, sexier
\nfrequency," he said.<\/p>\n
\nbespeak more desirable mates with larger bodies. It’s useful shorthand,
\nsince it’s hard to get a good look at one’s suitor if he is 80 feet
\nlong and swimming in murky water.<\/p>\n
\nnearly to extinction, they may have been spread so thin that they could
\nno longer find one another easily, prompting them to raise their pitch.<\/p>\n
\nto restrict whaling beginning in the late ’60s helped populations
\nrebound. With increased numbers, the whales may not have needed to
\nshout and may have gradually returned to their deep tones. <\/p>\n
\nhints that some of these great whales are recovering; it’s not all
\ndoom," said co-author Sarah Mesnick, ecologist at the National Oceanic
\nand Atmospheric Administration Fisheries Service.<\/p>\n
\nare related to population density, they might aid efforts to count blue
\nwhales, Hildebrand said. They once numbered in the hundreds of
\nthousands. Today, their population is thought to be 10,000 or so.<\/p>\n
\nJay Barlow, program leader at NOAA fisheries, cautioned that changes in
\nthe whales’ pitch don’t track closely with population changes.
\nCalifornia blues, for example, recovered most strongly in the ’70s and
\n’80s, and their numbers may not have grown much since, he said.<\/p>\n
\nBarlow had no alternate theory for the deeper songs, which he sometimes
\nplays on his home stereo. The sound makes his floor shake and upsets
\nhis cats.
<\/br>
<\/br>David Mellinger, a marine mammal bio-acoustician at
\nOregon State University, said that, whatever the reason, the finding
\n"is astonishing." It recalled to him the first time he heard a blue
\nwhale sing.<\/p>\n
\n"It was a defining moment in my life," he said. "It made a visceral
\nimpression on me. Just this huge animal. I could hear <\/em>the hugeness of it."<\/p>\n
<\/br><\/em><\/p>\n","protected":false},"excerpt":{"rendered":"