Dolphins prevent NZ shark attack
By Phil Mercer
BBC, Sydney
A group of swimmers has told how a pod of dolphins protected them from a great white shark off New Zealand's coast.
The lifeguards were training at a beach near Whangarei on the North Island when they were menaced by a 3-metre shark, before the dolphins raced in to help.
The swimmers were surrounded by the dolphins for 40 minutes before they were able to make it safely back to the beach.
Marine biologists say such altruistic behaviour is not uncommon in dolphins.
Lifeguard Rob Howes was in the water with two colleagues and his teenage daughter.
It was an uncomfortable experience, as they were circled by a great white shark, which came within a couple of metres.
He said around half a dozen dolphins suddenly appeared and herded the swimmers together. The mammals swam in tight circles to create a defensive barrier as the great white lurked under the surface.
The swimmers said the dolphins were extremely agitated and repeatedly slapped the water with their tails, presumably to try to deter the predator as it cruised nearby.
The drama happened in New Zealand three weeks ago, but only now are the lifeguards telling their story.
It is a day they will never forget, especially for one of the swimmers, who was on her first day as a volunteer.
They have no doubt that the dolphins acted deliberately to protect them.
Researchers have said they are not surprised. A marine biologist insisted that dolphins, which are considered to be one of the most intelligent mammals, "like to help the helpless".
Story from BBC NEWS:
http://news.bbc.co.uk/go/pr/fr/-/1/hi/world/asia-pacific/4034383.stm
Published: 2004/11/23 08:03:35 GMT
© BBC MMIV
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I can't help feeling sceptical about this one - don't understand
why this ability would be selected for. Can anyone explain?!
November 18, 2004 LA Times
In Evolutionary Race, Humans Went the Extra Mile, Study Says
Running for survival
November 18, 2004
By Robert Lee Hotz, Times Staff Writer
Humanity was born to run.
More than by brain size or tool-making ability, the human species was set
apart from its ancestors by the ability to jog mile after lung-stabbing
mile with greater endurance than any other primate, according to research
published today in the journal Nature.
Indeed, human beings evolved as the cross-country stars of a primordial
runner's world 2 million years before the advent of jogging shoes,
tracksuits and arthroscopic knee surgery.
Mounting a challenge to the conventional wisdom about human origins,
researchers at Harvard University and the University of Utah concluded
that the ability to run long distances was the driving force shaping the
modern human anatomy.
Such running ability could have given early humans a survival edge in
scavenging on the open savannas of Africa.
The earliest humans, the researchers said, were marathon men and women
from the tips of their distinctively short toes and long Achilles tendons
to the tops of their biomechanically balanced heads.
"We have gone all this time somehow missing this truly important aspect of
humans this [long-distance running] behavior and its impact on the design
of the human body," said University of Utah biologist Dennis Bramble, who
co-wrote the study.
"Primates don't do distance running," Bramble said. "We should have
recognized that humans are very odd."
In a detailed biomechanical analysis, Bramble and colleague Daniel
Lieberman at Harvard University suggested that distance running was not a
minor byproduct of the ability to walk upright on two legs.
It ultimately led to the development of the large brain that sets modern
humans apart from all other creatures.
If natural selection had not favored running, Bramble said, "We would
still look a lot like apes."
The researchers compared human anatomy to early apes and hominids and
found telling differences.
Take the distinctive bulge of the buttocks at the back of the human
silhouette. Humans have large, well-muscled buttocks that help stabilize
the body during running.
The muscles connect the femur the large bone in each upper leg to the
trunk and keep the body from over-balancing with each step.
Great apes, by contrast, have narrow hips and no rump to speak of.
Chimpanzees and gorillas walk on their knuckles. Humans have a lengthy
arm-swinging stride, as long in proportion for a human runner as that of a
galloping horse.
Long ligaments and tendons including the Achilles tendon serve as
springs that store and release mechanical energy during running. The
Achilles tendon on an ape is a mere stub.
The researchers also identified other anatomical features:
A more balanced head with a flatter face, smaller teeth and short snout,
compared with prehuman species. That makes it easier to balance the head
during the up and down shocks of running.
A ligament that runs from the back of the skull and neck down to the
thoracic vertebrae. It acts as a shock absorber and helps the arms and
shoulders counterbalance the head during running.
Wide shoulders that allow the body to rotate during running. A narrow
trunk, waist and pelvis allow the upper body to counteract the movement of
the legs.
The stiff arch of the human foot. That allows a runner to push off the
ground more efficiently and utilize ligaments on the bottom of the feet as
springs. Humans also have an enlarged heel bone for better shock
absorption, as well as shorter toes.
The new theory immediately stirred a scholarly controversy among experts
in biomechanics, human origins and comparative anatomy.
"I question whether endurance running was the evolutionary turning point
that helped morph us into our modern form," said anthropologist Ken
Mowbray at the American Museum of Natural History in New York. "I think a
lot of other things had to take place."
But Richard Klein, an expert in human origins at Stanford University,
said: "I think they make a strong case that, from the beginning, an
important advantage of modern bipedalism was that it facilitated
long-distance running."
Until now, the importance of running as an evolutionary force has been
lost in the debate over why humanity's early ancestors first evolved their
upright stance, said Christopher Ruff, director of the Center for
Functional Anatomy and Evolution at Johns Hopkins University.
Randall Susman, an expert in comparative early human anatomy at the State
University of New York at Stonybrook, said that humanity's pathetic
performance as a sprinter made the ability easy to overlook.
People are so slow in the short run that almost any dog can chase down a
fleeing human being, as many postal carriers have learned from experience.
When it comes to long-distance running, however, a healthy human jogger
can outrun most animals, sustaining a pace of 15 miles a day or more for
extended periods of time.
"That is an astonishing capability," said Lieberman, who specializes in
biological anthropology at Harvard. "Most animals can't do that.
"Generations of anthropologists have focused on walking and left running
completely out of the picture," he said. "But there are a lot of features
of our bodies that only make sense in terms of running."
The muscles, tendons and bone structures necessary for efficient
long-distance running are quite different from those needed for steady
walking.
"We don't appreciate how dramatic the differences between walking and
running are because the transition between them is so smooth," Bramble
said. "But the biomechanics are fundamentally different."