Monday, November 27, 2006

Humpbacks have humanlike brain cells

Cetaceans may have evolved infrastructure for intelligence before primates

"Humpback whales have a type of brain cell seen only in humans, the great apes and other cetaceans such as dolphins, researchers reported on Monday.

This might mean such whales are more intelligent than they have been given credit for, and suggests the basis for complex brains either evolved more than once, or has gone unused by most species of animals, the researchers said.

The finding may help explain some of the behaviors seen in whales, such as intricate communication skills, the formation of alliances, cooperation, cultural transmission and tool usage, the researchers report in The Anatomical Record.

Patrick Hof and Estel Van der Gucht of the Department of Neuroscience at Mount Sinai School of Medicine in New York studied the brains of humpback whales and discovered a type of cell called a spindle neuron in the cortex, in areas comparable to where they are seen in humans and great apes.

Although the function of spindle neurons is not well understood, they may be involved in cognition — learning, remembering and recognizing the world around oneself. Spindle cells may be affected by Alzheimer’s disease and other debilitating brain disorders such as autism and schizophrenia.

Islands in the cortex
The researchers said they found spindle neurons in the same location in toothed whales with the largest brains, which suggests that they may be related to brain size. Toothed whales such as orcas are generally considered more intelligent than baleen whales such as humpbacks and blue whales, which filter water for their food.

The humpbacks also had structures that resembled “islands” in the cerebral cortex, also seen in some other mammals."

Saturday, November 25, 2006

Is this Britain's unluckiest man?

"If you ever think life is being a little tough on you, just be grateful you aren't John Lyne – who could well be Britain's unluckiest man.

'Calamity John' has suffered 16 major accidents in his life, including lightning strikes, a rock-fall in a mine and three car crashes.

He is presently laid up again after falling down a manhole at work.

The 54-year-old industrial cleaner will be out of action for 32 weeks and is not sure he can return to his job.

The accident damaged his back and injured his left leg and both knees – which the grandfather-of-three can add to a lifetime of broken bones.

But none of this has left Mr Lyne bitter – he is just glad to be alive. 'Everyone thinks it is just hilarious,' he said. 'My mates, family and wife Susan just laugh about it.

'I don't think there is any reason or explanation. Things could have been much worse and I could have died but it doesn't worry me too much.'

Mr Lyne's mishaps cover a lifetime and he has even been known to suffer two accidents at once. As a child, he fell off a horse and cart – only to be run over by a delivery van.

When he was a teenager, he broke his arm falling from a tree.

On his way back from hospital, his bus crashed, breaking the same arm in another place. The date, of course, was Friday the 13th.

A philosophical Mr Lyne, of Stainworth, South Yorkshire, said: 'I have had a lot of lucky escapes and people have compared me with a cat with nine lives. It doesn't get me down. It is just how it is.'"

Thursday, November 16, 2006

Experts Say Tomb May Be Under Monolith

"Mexican archaeologists said on Thursday there are indications that the tomb of an Aztec emperor could lie beneath a recently-uncovered carved stone monolith showing a fearsome, blood-drinking god.

Researchers hope to begin removing the stone to explore a pit that lies beneath. A date carved on the stone and its unusual placement suggest it contains the remains of emperor Ahuizotl, the father of Moctezuma, the Aztec ruler defeated by the Spaniards.

Archaeologist Eduardo Matos said it would be the first burial ever found of a leader of the 1427-1521 Aztec empire."

Sunday, November 12, 2006

Manatees May Be Smarter Than We Think

"Back in 1902, a scientist examining the smooth, grapefruit-size brain of a manatee remarked that the organ's unwrinkled surface resembled that of the brain of an idiot.

Ever since then, manatees have generally been considered incapable of doing anything more complicated than chewing sea grass.

But Hugh, a manatee in a tank at a Florida marine laboratory, doesn't seem like a dimwit. When a buzzer sounds, the speed bump-shaped mammal slowly flips his 1,300 pounds and aims a whiskered snout toward one of eight loudspeakers lowered into the water. Nosing the correct speaker earns him treats.

Hugh is no manatee prodigy. Such sensory experiments, along with other recent studies, are revealing that sea cows aren't so stupid after all.

Researchers contend that if the plant-eating beasts seem slow-witted, it is because they faced no threats to their survival before the advent of boat propellers.

"They're not under any selection pressure to evolve the rapid-type behavior we've associated with hawks, a predator, or antelopes, a prey. They look like very contented animals that don't have very much to do all day," said Roger Reep, a neuroscientist at the University of Florida's College of Veterinary Medicine."

Saturday, November 04, 2006

Fish eavesdrop to avoid becoming dinner

"Fish can eavesdrop on the calls of dolphins to avoid getting eaten, a new study suggests.

"Probably a lot of fish can do this," said lead researcher Luke Remage-Healey, a behavioral neuro-endocrinologist at University of California, Los Angeles.

A bottom-dwelling fish found off the coast of Florida called the gulf toadfish is prime prey for dolphins, which often listen to toadfish calls to find their targets. In fact, 80 percent of bottlenose dolphin diets containing sound-producing fish. But whether the toadfish peels its “ears” toward dolphins has remained a mystery.

Remage-Healey first suspected that gulf toadfish could listen in on hungry dolphins' calls two years ago while recording the mating calls of the male toadfish off the Gulf coast of Florida. The fish were hanging out above their nests.

"Then, they all stopped calling," Remage-Healey recalled. "My field assistant noticed dolphins foraging right over the toadfish site, and we heard we were recording dolphin sounds instead."

The researchers captured toadfish and placed each in its own cage and rested the cages on the seabed in the breeding patch. From underwater speakers, they played recordings of snapping shrimp sounds or dolphin sounds — both high-frequency "whistles" that dolphins use to communicate with each other, and low-frequency "pops" likely used to locate a quarry. The shrimp sounds mimicked a common background noise in the bay.

Results showed that the toadfish ignored the snapping shrimp sounds and dolphin whistles and continued on with their mating calls. But when the fish heard dolphin pops or combinations of pops and whistles, they drastically reduced their calling rates.

Prior research revealed that toadfish hear low-frequency sounds best, consistent with the drastic response to the recordings of low-frequency pops.

As confirmation, measurements of toadfish blood taken immediately after the dolphin sounds were played revealed that levels of the stress hormone cortisol shot up after they heard pops.

Remage-Healey, Douglas Nowacek of Florida State University and Andrew Bass of Cornell University in New York report their findings in the Nov. 15 issue of the Journal of Experimental Biology."