13 March 2014


Researchers say a fossilized whale skull pulled from sandy muck outside Charleston, S.C. indicates that biosonar was being used over 32 million years ago. It also indicates that toothed whales were stranding in the sand over 32 million years ago.

These same researchers inform that ancient toothed whales had air sinuses in their heads that enabled their biosonar system. This means that undersea earthquakes have been causing toothed whales to strand in the sand for at least 32 million years. 

The Christian Science Monitor
Pete Spotts / March 12, 2014,

Sperm whales do it. Dolphins do it. Orcas do it. And now, researchers have unveiled the fossilized skull of a 28-million-year-old marine mammal that did it too – used sound to find its next meal or swim safely through turbid waters.

After comparing the nearly complete skull with those of other fossil cetaceans, the team placed C. macei on the evolutionary tree just above the common ancestor to all toothed cetaceans. That branch of the whale family uses echolocation to find its food, unlike their cousins who feed by straining seawater through boney baleen plates. Right and humpback whales are modern examples of these strainers.

The study "provides an important new piece of information on when echolocation originated, such that it originated almost immediately after the split between baleen whales and toothed whales," notes Frants Jensen, a researcher at the Woods Hole Oceanographic Institution in Woods Hole, Mass., who studies marine echolocation.

Researchers have long been interested in the evolution of this natural sonar, or echolocation, in marine mammals because it's a complex way of finding prey or navigating.

Sperm whales, the largest toothed whales on the planet, echolocate by sending out relatively widely spaced, sharp clicks – comparable to the sound of hitting too spoons together. Some searchers have noted that each whale has a unique rhythm that allows it to distinguish the sounds it sends from those of other whales. Dolphins echolocate with a series of tightly-space clicks that resemble the sound of a creaking hinge on a slowly opening door.

The pitch and timing of an animal's echolocation often is tailored to its surroundings. Harbor dolphins, for instance, use a frequency that falls within a narrow window of relative silence amid the clutter of underwater noises in a harbor. The pitch and the pattern the dolphins use make it difficult for hungry orcas to find them, according to bioacoustic scientists Lee Miller and Magnus Whalberg at the University of Southern Denmark.

With the newly described C. macei, New York Institute of Technology researcher Johnathan Geisler and two colleagues have opened a window on the early evolution of this capability among toothed cetaceans.

The skull was unearthed from a drainage ditch that forms one boundary of a housing development in College Park, S.C.

Construction of these developments began in the 1970s, and as the drainage ditches were dug, "they hit this really rich, muddy sand that's produced a huge number of fossil cetaceans," Dr. Geisler says. "You never know what you'll find in your backyard."

Yet while the fossils have piled up, few have been formally described. The skull Geisler and his colleagues analyzed came from this collection, which is housed in the Mace Brown Natural History Museum at the College of Charleston.

Even before the team explored the more-subtle evidence for C. macei's primitive echolocation tools, two aspects of the skull leaped out as highly unusual, Geisler says.

"Cetaceans have very strange skulls, particularly the toothed whales, dolphins, and porpoises," he explains. Many of the bones associated with the snouts, or rostrum, extend back to cover much of the skull – a feature known as telescoping. It's a feature that becomes more pronounced as ancient lineages of toothed cetaceans evolved into today's animals.

The newly described skull shows a degree of telescoping usually seen in today's cetaceans, he continues. And it isn't seen in other members of the extinct family to which this species belongs.

In addition, skulls of toothed cetaceans aren't symmetrical. For instance when two halves of the skull fuse as the young mature, the line marking the junction is off center. This specimen displayed that offset. In addition, when looked at head on, the face was twisted slightly counterclockwise. One sinus was noticeably larger than the other. As with telescoping, this asymmetry in the skull was far more pronounced than one might expect in a specimen this old.

"There were a lot of enigmas with this specimen," he says.

As the team analyzed the skull, they also found deep cavities they they eventually interpreted as the locations of air-filled sinuses. Such sinuses play key roles in echolocation. After identifying these features, the team found others that have been associated with echolocation in modern toothed whales, dolphins, and porpoises. Even the extent of telescoping fell into place, since the bones would have helped support the complex array of muscles involved in generating, aiming, and receiving the sounds.

If C. macei was able to echolocate, it suggests that this capability first evolved in toothed cetaceans between 35 million and 32 million years ago, the researchers say.

Reflecting on the somewhat pedestrian site that yielded this and other marine fossils outside of Charleston, Geisler acknowledges that "there is a natural pull in our field to do something really exotic. There's a logic behind it because often people aren't looking in these places. But it doesn't mean  that there may not be something really cool close to home. This is definitely one of those cases."


Site Map for http://deafwhale.com  

Dec 09: Whale Dangerous Earthquake South of Perth 
Dec 09: Seaquake causes dolphins to strand Baja California   
Nov 23: Seaquakes kill 322 baleen whales in Chile    (shocking)  
Aug 24: NOAA whale scientists dumbfounded   
Aug 14: stranded dolphin is determined to be deaf   
Aug 08: seaquake causes pilot whales to strand Nova Scotia   
Jul   27: is our stranding solution flawed as scientists claim   
Jun  01: pilots stranded Isles of Skye from Reykjanes Ridge   
May 22: dead whales washing ashore on the California Coast   
May 10: earthquake kills 20 Sei Whales near Chile Coast   
Apr  10: seaquake strands 150 melon-headed whales in Japan   

Dec 25: navigation failure in mass stranded whales  (most popular)   
Dec 08: seaquake causes 7 sperm whales to beach Australia   
Nov 24: seaquake beaches 3 sperm whales at Golden Bay   
Nov 04: seaquake beaches 60 pilot whales in Bay of Plenty   
Oct 29: nine pilot whales strand on Prince Edward Island   
Apr  11: 60 pilot whales beach in Bay of Plenty   
Mar 20: Cape Ray Newfoundland 37 dolphins beach   
Mar 14: undersea quakes louder than nuclear explosions   
Mar 13: seaquakes cause whale strandings 32 million years   
Mar 02: blue whale killed by seaquake in Kuwait   
Feb 27: seaquake kills young killer whale   
Feb 23: predicting mass beachings based on seaquakes   
Feb 21: lessons in understanding why whales beach   
Feb 18: seaquake Greenland Sea kills 3 sperm whales   
Feb 12: nine orcas killed by seaquake   
Jan 30: Cape Cod mass stranding predicted   
Jan 20: seaquake causes 39 pilot whales to strand Florida   
Jan 16: seaquakes beach 65 pilot whales in Golden Bay   
Jan 05: seaquake beaches 30 pilot whales in Golden Bay   

Dec 06: why did pilot whales beached in the everglades?   
Apr 30: seaquake beaches 6 killer whales in Iceland   
Apr 25: beached whales stop war games   

Dec 08: seaquake beach pilot whales South Carolina   
Nov 15: pilot whales beach at Golden Bay, New Zealand   
Nov 04: seaquake causes two pods to beach at King Island   
Oct 28:  pilot whales strand on North Andaman Island   
Oct 17: earthquakes cause New Zealand whale stranding   
Sep 09: earthquake kills pregnant sperm whale   
Sep 03: seaquake strands pilot whales in Scotland   
Aug 24: two quakes cause near beaching in Cape Verde   
Jul  28:  200 Pilot Whales Northwest of Iceland   
Mar 19: Four Sperm Whales Wash Ashore in China   

Dec  31: world's rarest whales killed by earthquake   
Mar 06: 52 melon-headed dolphins strand in Japan   

Nov 20: 52 Pilot Whales Stranded in Tasmania


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